Consider the following algorithm

for $($i$=1$; i$<=1\mathrm{.}5*$n; i$++)$

system.out.print$($i$)$;

for $($i$=$n; i$>=1$; i$--)$

system.out.print$($i$)$;

What is the output when n$=4$

a$.12344521$

b$.$ None of the above

c$.1234564521$

d$.1234564321$