The "unique or single effect" that Poe is attempting to express in this passage is B. SORROW.
It shows how she has waited for a long time to be loved by the person she has loved. That person is the "me" in the poem.
Many and many a year ago depicts a very long time of unrequited love or a one-sided love at stated by the text "no other thought than to love and be loved by me".
Answer:
12.5
Explanation:
Divide 7.50 by 3 and you will get 2.5
Now you multiply 2.5 x 5