How Do $\pi$ Bond Electrons Differ From $\sigma$ Bond Electrons in C == C Bonds?
A)

How do $\pi$ bond electrons differ from $\sigma$ bond electrons in C == C bonds?

A) $\pi$ bond electrons are located along the bond axis, and $\sigma$ bond electrons are located above and below the plane of the bond axis.
B) $\pi$ bond electrons are more tightly bound that $\sigma$ bond electrons thus explaining why double bonds are stronger than single bonds.
C) $\sigma$ bond electrons dominate the reactivity patterns of ethylene as they are more readily accessible.
D) $\sigma$ bond electrons are located along the bond axis, and $\pi$ bond electrons are located above and below the plane of the bond axis.
E) Both kinds of electrons are essentially equivalent.