The correct answer is C, the Cx agent for the project must conduct or oversee the Cx of the PV system. According to the LEED v4 Reference Guide for Building Design and Construction, the Energy and Atmosphere Prerequisite, Fundamental Commissioning and Verification, requires that all energy-related systems, including renewable energy systems such as PV, be commissioned by an independent commissioning agent (CxA) or a qualified member of the project team who reports to the owner. The CxA or the qualified team member must perform or oversee all commissioning activities, including developing a commissioning plan, reviewing design documents and submittals, verifying installation and performance, and preparing a commissioning report12 Reference: 1: LEED v4 Reference Guide for Building Design and Construction, Energy and Atmosphere Prerequisite: Fundamental Commissioning and Verification, page 562. 2: LEED v4 Reference Guide for Building Design and Construction, Glossary, page 1020.

Detailed
In a cold climate, additional envelope insulation is the most effective strategy for reducing energy costs. Improved insulation minimizes heat loss through the building envelope, reducing the demand for heating systems. This aligns with LEED's focus on enhancing energy efficiency and thermal performance in building design.

Installing a vegetative roofing system is the best option to address the potential glare resulting from a project's highly reflective roof. A vegetative roofing system, also known as a green roof, is a roof that is partially or completely covered with vegetation and a growing medium, planted over a waterproofing membrane. A vegetative roofing system can reduce the reflectivity of the roof surface and mitigate the glare impact on the surrounding environment. It can also provide other benefits, such as reducing heat island effects, improving stormwater management, enhancing biodiversity, and increasing roof insulation. Therefore, option A is the correct answer. The other options are not as effective or desirable as installing a vegetative roofing system. Changing the design to reduce the amount of roofing area (option B) may not be feasible or desirable, as it may compromise the project's program or performance. Changing the roofing material to a dark material to eliminate the issue (option C) may reduce the glare, but it will also increase the heat absorption and emission of the roof, contributing to heat island effects and increasing cooling loads. Increasing the parapet height (option D) may block some of the glare, but it will also increase the material and construction costs, and it may not be sufficient to prevent glare from all angles. For more information on vegetative roofing systems and their benefits, you can refer to the LEED v4 Reference Guide for Building Design and Construction1 or the Green Roofs for Healthy Cities website2.

The heat island effect is the phenomenon of urban areas having higher air temperatures than surrounding rural areas due to the absorption and emission of heat by human-made surfaces, such as buildings, roads, and pavements. The heat island effect can have negative impacts on the environment, human health, and energy consumption. One of the strategies to reduce the heat island effect is to use highly reflective paving materials that have a high solar reflectance index (SRI), which measures the ability of a surface to reflect solar radiation and stay cool. However, over time, the paving materials can accumulate dirt and dust, which can lower their reflectance and increase their heat absorption. Therefore, a facility manager cleaning highly reflective paving material is reducing the heat island effect by restoring the reflectance and cooling potential of the surface12.
Reference:
* Heat Island Reduction | U.S. Green Building Council1
* SpecTopics: Heat Island Reduction Credit and LEED V4/V4.1 - Carlisle SynTec

USGBC's vision for using LEED internationally is to promote green building practices that are globally applicable, locally relevant, and culturally sensitive1. To achieve this vision, USGBC provides opportunities for alternative compliance paths (ACPs) that meet the unique needs of a particular region, such as climate, codes, standards, market conditions, and priorities2. ACPs are modifications or additions to existing LEED credits or prerequisites that recognize regional differences and allow for more flexibility and applicability of LEED3. ACPs are developed by USGBC in collaboration with local green building councils, experts, and stakeholders, and are reviewed and approved by the LEED Steering Committee3. ACPs are available for various regions and countries, such as China, India, Brazil, Europe, and Canada2.
Reference:
LEED International | U.S. Green Building Council
Alternative Compliance Paths (ACPs) | U.S. Green Building Council
USGBC's 2020 vision will use LEED to further global connectedness | U.S. Green Building Council LEED Reference Guide for Building Design and Construction v4