Which one of these is the correct formula for computing the return on a portfolio comprised of unequal amounts of stocks A$,$ B$,$ and C$?$

Multiple choice question.

Rp $=($RA $+$ RB $+$ RC$)/3$

Rp $=($wA $+$ wB $+$ wC$)\backslash$times $[($RA $+$ RB $+$ RC$)/3]$

Rp $=($wA $\backslash$times RA$)+($wB $\backslash$times RB$)+($wC $\backslash$times RC$)$

Rp $=[($wA $\backslash$times RA$)+($wB $\backslash$times RB$)+($wC $\backslash$times RC$)]/3$