In the given question, we have to choose the option with an error.
Option
A is grammatically correct because 'but' is a coordinating conjunction
which links the first two phrases, hence option A does not have an
error.
Option B does not have an error because it is grammatically correct.
We
choose option C which has an error because the comparison is being made
between two individuals, hence it's of a comparative degree. The
underlined word is a superlative adjective whereas the adjective used
should be 'better' which is a comparative, in place of 'best'.
Option
D does not have an error because the verb 'is' is linked to the
singular noun 'choice' and it's in present tense as is the tense of the
sentence.