Consider the statement, "For all integersaandb, if the product ofaandbis even, thenais even orbis even."What would be the beginning of a direct proof of this statement?

Group of answer choices

1. Assume thatais even orbis even. Thena or b= 2kfor some integerk.We must show that eitherais even orbis even, so it suffices to show one or the other.
2. Assume thatabis even. Thenab= 2k+1 for some integerk.We must show that eitherais even orbis even, so it suffices to show one or the other.
3. Assume thatabis even. Thenab= 2kfor some integerk.We must show that eitherais even orbis even, so it suffices to show one or the other.
4. Assume thatabis even. Thenab= 2kfor some integerk.We must show thatais even andbis even.