For which species below would $H_f^o$ be zero?

$2C{o}_{(s)}+H_{2(g)}+8P{F}_{3(g)}2$HCo$(P{F}_3{)}_{4(l)}$

A$.Co$

$($s$)$

C$.P{F}_{3(g)}$

E$.$ both $C{o}_{(s)}$ and $H_{2(g)}$

B$.H_{2(g)}$

D$.$ HCo$(P{F}_3{)}_{4(l)}$