QA$\mathrm{.}7)$ When an N$-$digit positional number system with a radix $($base$)R$ is used, what

is the weight of the least significant digit if the number has no digits situated at right

hand side of the radix point?

$R^{-N+1}.$

$R^{-N-1}.$

$R^1.$

$R^0.$