If$$ A$,$ B$,$ and C are$$ variables, which of the following is a valid constraint for a linear$$ program?

Part $2$

A$.$

$2$A$+5$B$<=300$

B$.$

A$$Superscript$2$

$>=100$

C$.$

$3$AB$+4$C$>=50$

D$.$

$4$BC$<=150$