Which second degree polynomial function f of x has a leading coefficient of 3 and roots 4 and 1 ?
A
f of x is equal to 3 x squared minus 5 x plus 4B
f of x is equal to 3 x squared plus 15 x plus 12C
f of x is equal to 3 x squared plus 5 x plus 4D
f of x is equal to 3 x squared minus 15 x plus 12