Catalyst or triggering event
This is a metaphor. the definition of a metaphor is, a figure of speech in which a word or phrase is applied to an object or action to which it is not literally applicable
Imagery can be used in poetry for a range if different things. Some of them include expanding the readers imagination which can also build curiosity and cause them to want to carry on. It is a great engaging technique and it adds detail to the writing.
<span>It is "D. open-market
operations" that is a tool the Federal Reserve uses to influence the
volume of money in the economy by buying and selling government
securities. </span>
