Pick out the sentence which is grammatically correct?
AOne should not waste his time
BThe boy who does best he will get a prize
CI asked for his book, but he did not lend me
DHe has been studying hard for the last two weeks
AOne should not waste his time
BThe boy who does best he will get a prize
CI asked for his book, but he did not lend me
DHe has been studying hard for the last two weeks