Consider the following algorithm

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

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

for $($i$=$n; i$>=2$; i$--)$

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

What is the output when n$=4$

a$.$ None of the above

b$.12345654521$

c$.12345664321$

d$.123456432$