Mark the letter A, B, C or D on your answer sheet to indicate the sentences that combines each pair of sentences in the following questions.
Question:
He was overconfident. Therefore, he ruined our plan completely.
A. It was because his overconfidence that ruined our plan completely.
>
B. He was overconfident, which ruined our plan completely.
>
C. That he was overconfidence ruined our plan completely.
>
D. It was his overconfidence ruined our plan completely.
Answer the question before viewing the answer below

Correct answer B
S + V, which + V + …