Answer:
B) new gimmicks.
Step-by-step explanation:
In this poem, the author talks about advertising, and how relentless it can be. He talks about how advertisers are able to find absolutely anyone that is in their target demographic in order to try to sell to him or her. He also describes how, in order to entice these people, advertisers add "marshmallows." In this case, marshmallows simply refers to the many new gimmicks that advertisers come up with in order to persuade potential buyers.