Selected fields are fields that you choose to display in your search results by clicking on them in the Fields sidebar or by using the fields command2. Selected fields are displayed below each event in the search results, along with their values2. Therefore, option A is correct, while options B, C and D are incorrect because they are not places where selected fields are displayed.

Event types allow users to assign labels to events based on predefined search strings. This helps categorize data and makes it easier to reference specific sets of events in future searches.
References:
Splunk Docs - Event types

Event types in Splunk are saved searches that categorize data, making it easier to search for specific patterns or criteria within your data. When saving an event type, the search must essentially filter events based on criteria without performing operations that transform or aggregate the data. Here's a breakdown of the options:
A). The search index-server_472 sourcetype-BETA_494 code-488 | stats count by code performs an aggregation operation (stats count by code), which makes it unsuitable for saving as an event type. Event types are meant to categorize data without aggregating or transforming it.
B). The search index=server_472 sourcetype=BETA_494 code=488 [ | inputlookup append=t servercode.csv] includes a subsearch and input lookup, which is typically used to enrich or filter events based on external data.
This complexity goes beyond simple event categorization.
C). The search index=server_472 sourcetype=BETA_494 code=488 | stats where code > 200 includes a filtering condition within a transforming command (stats), which again, is not suitable for defining an event type due to the transformation of data.
D). The search index=server_472 sourcetype=BETA_494 code-488 is the correct answer as it purely filters events based on index, sourcetype, and a code field condition without transforming or aggregating the data.
This is what makes it suitable for saving as an event type, as it categorizes data based on specific criteria without altering the event structure or content.

Macros in Splunk are defined with the number of arguments inside parentheses after the macro name. For two arguments, the syntax is samplemacro(2). This defines a macro accepting two arguments.
Reference:
Splunk Power User Study Guide, Knowledge Objects Section
Splunk Docs: Macros
"Macros with arguments are declared with the number of arguments inside parentheses."

Reference: https://docs.splunk.com/Documentation/SplunkLight/7.3.5/GettingStarted/Designdatamodelobjects A root event dataset is the base dataset for a data model that defines the source or sources of the data and the constraints and fields that apply to the data1. A root event dataset has two parts: constraints and fields1. Constraints are filters that limit the data to a specific index, source, sourcetype, host or search string1. Fields are the attributes that describe the data and can be extracted, calculated or looked up1.
Therefore, option C is correct, while options A, B and D are incorrect.