The correct sentence is:
C Robin Hood's favorite weapon was a bow and arrow.
In this sentence, "bow" is used correctly, referring to the weapon. The other options have either incorrect usage or spelling. For example, option A uses "bough," which means a tree branch instead of "bow." Option B incorrectly uses "bow," as the context suggests the act of bending rather than the weapon. Option D spells "beau," which refers to a boyfriend or male admirer, instead of "bow."