Correct Answer: B
Explanation:
A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons. The carbanion exists in a trigonal pyramidal geometry. Formally, a carbanion is the conjugate base of a carbon acidand it is also a nucleophile.
R3C-H + B− → R3C− + H-B