Final answer:
A 'notorious complainer' is someone who is famous or well-known for their habit of complaining frequently, which corresponds to option a.
Step-by-step explanation:
The phrase 'notorious complainer' refers to someone who is well known for complaining. The word 'notorious' is commonly used to describe someone who is famous or well known for a negative trait. Therefore, the correct answer to the question is 'a. is well known for complaining.'
This means that option a. is correct. When someone is notorious for complaining, it means that their habit of complaining is well known and established. This can be due to their constant complaints or the way they express their dissatisfaction.