Please I need help for this

Let the closed interval [a , b] be the domain of function f. the domain of f(x - 3) is given by (a) the open interval (a , b) (b) the closed interval [a , b] (c) the closed interval [a - 3 , b - 3] (d) the closed interval [a + 3 , b + 3]

An air conditioning system can circulate 350 cubic feet of air per minute. how many cubic yards of air can it circulate per minute?

With alll of except for the 2 that i did already