Answer: A topic sentence
Step-by-step explanation:
A topic sentence is a type of sentence that gives summary to the main concept contained in a paragraph. It is most times the first sentence that starts a paragraph. A topic sentence is also called Focus sentence.
It must be noted that not all paragraph starts with a topic sentence.
Writing a good topic sentence involves.
a. Identifying and stating the main idea in an understandable manner.
b. It must be short and captivating.
c. Opinions must be reasonably presented.