Which of the following must be true for an expression to be a difference of 2 squares

Of four agents alpha, beta, gamma anddelta, three have to be sent together on amission. if alpha and beta cannot gotogether, beta and gamma cannot go togetherand gamma and delta cannot go together,then which of the following holds? 1. any three agents can be sent.2. alpha, delta and any one out of beta andv gamma can be sent.3. beta, gamma and any one out of alphaand delta can be sent.4. the mission is impossible.

Time's up got my coins up, my bars up, soon we find 'em we gon' slide 'em, we lined 'em, straight reclined 'em pistol grip, i got all kinds of, i'm not your driver shot gon' hit him, he won't answer, i'm blowin’ ganja so much work, they call me old school, i remind ya that bisshhh you think you got is not you, where you find her? she a kickstand, a big fan, i get behind her then i slid it in, i win, i win, ayy

Why are gold and platinum used for jewelry