Which ONE of the following money market instruments is most commonly issued for the purpose of funding banks in South Africa?

$($a $)$ Commercial paper bill

$($b $)$ Bankers$$ acceptance $($BA$)$

$($c $)$ Negotiable certificate of deposit $($NCD$)$

$($d $)$ Reserve Bank debenture $($RBD$)$

$($e $)$ None of the above