The correct option is D sings like a lark
A simile is a figure of speech that presents the likeness
between two unlikely things and contains the words 'like' or 'as'. For
example,
as smooth as butter, light like a feather and so on. In the given
sentence, "like a lark" compares the person's singing to that of a lark, as larks are known for their melodious singing, hence it's a simile and option D is correct. "Listen" is a verb and does not compare anything. "All day" is a phrase made up of an adjective and a noun, respectively, it's not a simile. "She sings" is a phrase made up of a subject and a verb, respectively. These three options are not similes and hence options A, B and C are incorrect.