instruction:
You are given a sentence, a question and two answer options ('A' and 'B'). Your task is to find the **incorrect** answer (return the string of the incorrect option, not A/B).
question:
Sentence: Karl is trying to light a match on his pant legs with very little success. He finds a piece of rough leather to strike the match against and the match lights up in no time. Question: Which surface provides more friction for heat? (A) PANT LEG (B) ROUGH LEATHER
answer:
PANT LEG


question:
Sentence: Lane is testing how strong gravity pulls on different objects. She drops a brick and a penny from a roof at the same time. Question: Which has larger mass and hits the ground first? (A) brick (B) penny
answer:
penny


question:
Sentence: One of Sarah's neighbors spilled dog food all over the stairs. The dog food pieces are on three stairways and all over the landings. Sarah gets mad and kicks a piece of dog food. The dog food flies across the wooden planks from one side of the staircase landing to the other. The dog food reaches the neighbor's door mat. It moves a few inches across the doormat. Question: Why didn't the dog food move further across the doormat? (A) The door mat is a spikier surface (B) the staircase landing is a spikier surface
answer:

the staircase landing is a spikier surface