In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No error'.

The reason for (a)/ his failure is because (b)/ he didn't study at all. (c)/ No Error (d)

A

The reason for 

B

his failure is because

C

he didn't study at all

D

No Error