The correct answer is D. There is a change in mood from the quatrains to the final couplet. This is common in the English sonnet that the final couplet is used to change the mood and add new meaning to what was previously said, thus being a sort of a peak for the sonnet.
The last one or D. The way that something is transmitted. This is because it says broadcasting. That suggests that something is being sent out to everybody. In this case it just means that it is being announced throughout the school.
A repeated sequence of meter composed of two or more stressed and unstressed beat is called a poetic foot. if the beat is only an unstressed and stressed following each other in sequence, that is called an iambic foot.