To check if the liked list is full

Select one:

a$.$ node $*$temp $=$ new node$()$; if$($temp$->$next $==0)$

b$.$ If $($head$==0)$

c$.$ node $*$temp $=$ new node$()$; if$($head$!=0)$

d$.$ node $*$temp $=$ new node$()$; if$($temp$==$NULL$)$