The running time T$($n$),$ where $\text{'}$n$\text{'}$ is the input size, of a recursive algorithm is given as follows:

T$($n$)=$ C$+$ T$($n$-1),$ if n$>1$

d$,$ if n$<=1$

The order of this algorithm is

a$.$ n$^3$

Ob$.$ n

c$.$ n$^$n

Od$.$ n$^2$