Hmm.. I believe it's 3. sorry if it's wrong. Use commas to separate independent clauses when they are joined by any of these seven coordinating conjunctions: and, but, for, or, nor, so, yet. ...
I would believe B is the answer because it is hinting that Johnny should be doing his homework, but instead he is outside playing.
The correct answer is metaphor.
A metaphor is a rhetorical figure of speech where two or more things are symbolically compared, without using the words such as like or as (because that would be a simile). This whole poem is symbolical/metaphorical - it talks about the passage of time and how everything is transient and fleeting.
