suppose a C$/$C$++$ array "data" was originally declared to have $10$ elements as follows:

int nElements $=10$;

double data $[$nElements$]$;

how can the array size be increased to $20$ elements?

a$.$ by changing variable nElements to $20$

b$.$ by redeclaring data as "double data$[20]$;$"$

c$.$by storing a number in $20$th position of data$[].$

d$.$error

e$.$impossible