Which One of the Following Statements Is True in Relation

Which one of the following statements is true in relation to the offence of abetment?

A) It is not necessary that the offence for which abetment is alleged should have been committed.
B) Unless an offence is successfully committed, there is no question of abetment
C) For the offence of abetment to be established, the abettor should have been proved to have done something at the time.
D) For the offence of abetment to be established, the abettor should have been proved to have done something at the time of commission of the offence itself to help its commission.