Correct answer is B

Create a Code Snippet
Use code snippets in Marketing Cloud Content Builder to save reusable bits of HTML, AMPscript, and Guide Template Language. Insert snippets when editing HTML via the Code Snippets toolbar selector, or by typing the Customer Key value for the snippet followed by the Tab key. You can also create a code snippet content block by clicking Create > Content Blocks > Code Snippet. You can reference Code Snippets with the AMPscript ContentBlockByKey and ContentBlockByID functions.
Link: https://help.salesforce.com/s/articleView?id=sf.mc_ceb_content_builder.htm&type=5

Correct: B