The correct answer is modified block.
The two most common formats for a business letter are block and modified block. In block style the business letter has all its text formatted and justified left, in modified block there is a change in the style's format of the details about the sender, receiver, date, address, these details are formatted in centre.
It is a simile because it is a figure of speech involving the comparison of one thing with another thing of a different kind, used to make a description more emphatic or vivid.
Answer:
Tom
Explanation: Subject answers to a question Who? So in this case Tom is the one that did something, aka offered you a piece of cake.