The main idea of a poem is also known as the: a. meterb. soundc. subjectd. type

The answer is C: subject.

Poetry, like any other form of literature, usually treats a subject matter or topic. A subject is the underlying idea that is thematically explored in a work of poetry, but the subject should not be confused with the theme of a poem. In colloquial terms, a subject is the topic elaborated upon in the poem, and the theme is, most commonly, the poet´s personal perspective on the subject matter.    

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.

one thousand and one nights, also known as arabian nights is a collection of stories whose basic structure is that of embedded narrative. this technique refers to a main story which works as the common frame - or framing narrative - for the other stories, and then this series of stories which are connected to the main one. this technique can also be referred to as a story within a story. the stories stem from the original tale, some begin and end on their own, some are connected to the previous or following one, by means of questions that are answered in the subsequent tale, or characters which reappear.