A well-written paragraph should begin with a(n)

A) conclusion.
B) topic sentence.
C) idea from the previous paragraph.
D) noun.

Topic Sentence

The sentence in a paragraph that summarizes the main idea or point the paragraph is intended to convey.

Paragraph

A distinct section of a piece of writing, usually dealing with a single theme and indicated by a new line, indentation, or numbering.

Conclusion

The final part of a document or speech that summarizes the main points or findings.