R Takes a Loan from M on the Security of His

R takes a loan from M on the security of his bike. But when M was away. R took away the vehicle. The loan was not repaid. R is guilty of:

A) No offence as the bike belonged to him
B) No offence as what he owes is some money that could be repaid.
C) Theft as he takes away the vehicle from the possession of M with dishonest intention.
D) Dishonest misappropriation of property as he had no right to appropriate the property.