Comprehensive and Detailed Explanation:
A restricted market is characterized by high barriers to entry, often due to stringent government regulations and the need for substantial financial investment. These factors limit the number of new entrants, resulting in a market dominated by a few established suppliers. While existing suppliers may offer excellent services, the key defining features of a restricted market are the regulatory constraints and the significant capital required to compete.
Reference:
CIPS L4M6 Study Guide

The four categories are; Minimal effort, manage closely, keep informed, keep satisfied. You can see the Matrix on p.81. An easy way to remember this is there are 2 Ms and 2 Keeps. And these sit on opposite sides of the matrix.

The correct answer is 'The product is easy to source elsewhere'. The other three are given as reasons a marketplace might be restricted on p.138. Other reasons also include; brand loyalty, difficult access to distribution channels, and companies colluding.

They could outsource cleaning and facilities management. These are auxiliary services. The manufacturing of bike parts is their 'core' business so they should retain this in-house

For partnerships to succeed, both buyer and supplier must see significant value in the relationship. High spend indicates strategic importance, ensuring mutual commitment. If the buyer is a core customer for the supplier, and has a high spend, partnership sourcing is mutually beneficial.