What is the topic sentence for this passage?

a. Sentence 1

b. Sentence 2

c. Sentence 4

d. There is no single topic sentence.

the one that should be the topic sentence is: A. Sentence 1 The topic sentence should state the main idea/the main topic that the writer wished to convey through the writin. So it would be very effective to put it on the first sentence of an excerpt

Unfortunately, we are not given with the passage so that we will be able to identify the topic and answer this item. However, it should be noted that the topic of the passage is usually the first sentence of the passage so readers can already grasp the idea. The answer is therefore letter A.