A run-on sentence usually occurs when two separate sentences or clauses are improperly combined. However, unlike sentence fragments, run-on sentences can still be technically grammatically correct. So technically the are bad.
★ Formula Applied :




★ Explanation :

Lets use substitution method ,
Let , u = sin2x
⇒ du = 2.cos2x.dx





★ Alternate Method :




]

The both try to help the reader understand the book and cnflict
I believe the answer is B