Instruction: Evaluate each product title in the given list, assess its relevance to the given query, and then arrange the products in descending order of relevance, with the most relevant product at the top of the ranked list.

Input:
Query: mens cotton undershirt
Product list:
A: TIANRUN Men's Slim T-Shirts Muscle Cotton Crewneck Short Sleeve Undershirts Gray
B: Alfani Men's Cotton V-Neck Heathered Undershirt in Purple Heather (X-Large)
Answer: A,B