Assume That $\mathrm{E}$ And $\mathrm{F}$ Are Events $\mathrm{E}$ And $\mathrm{F}$ Also Be an Event? Must the Intersection Of

Assume that $\mathrm{E}$ and $\mathrm{F}$ are events. Must the union of $\mathrm{E}$ and $\mathrm{F}$ also be an event? Must the intersection of $\mathrm{E}$ and $\mathrm{F}$ also be an event?

A) Only the union must be an event.
B) Neither the union nor the intersection must be an event.
C) Only the intersection must be an event.
D) Both the union and the intersection must be events.