Assume that for input size n $=16,$ the implementation of a certain algorithm A takes $1$ nanosecond

$($ns$)$ to run. How many nanoseconds will it take to run an input size of n $=64,$ if the time complexity of A

is

$($a$)$ O$($log n$)$

$($b$)$ O$($n$)$

$($c$)$ O$($n log n$)$

$($d$)$ O$($n$^2)$