Question 42: Mark the letter A, B, C, or D on your answer sheet to indicate the undelined part that needs correction in each of the following questions: It is a good idea to be careful in buying or purchasing magazines from salespersons who may come to your door.
Buy and Purchase are 2 synonyms, so here only one of them is used.
It’s a good idea to be careful about buying magazines from salespeople who may come to your door.
Answer C.
===============