Is anyone down to talk

type of error:

the error in the sentence is a "dangling modifier". a dangling modifier is a phrase, word or clause that "dangles" because there is not target to modify. in this case, "after mopping the floor" is the dangling modifier since it has no word to modify. the noun "house" cannot mop the floor; therefore there is a mistake in the writing of the sentence.

the correct answer is a. he fairs had detailed, specific rules about what merchants could sell and how they could sell it. despite the fact that all the other answers have relevant details, they make inferences based on the passage that lacks all relevant information to support them. only the answer a makes no inferences, and can be supported by this part of the passage: "the fairs were very well organized. they featured covered galleries so that merchants could buy and sell even if rain came drumming down; cellars were so large, they resembled underground cities. at the fairs, merchants could trust the weights and measures, and a strict order prevailed for how things were to be sold."

to make us smart. and also that they can get all the children in one place so they can shoot em all up.