The local linear approximation of a function f will always be greater than or equal to the function's value if, for all x in an interval containing the point of tangency,

(a) f ' less than 0

(b) f ' greater than 0

(c) f '' less than 0

(d) f '' greater than 0

(e) f ' = f '' = 0

I need to be able to answer the question and explain why but I am not even sure what they mean by "local linear approximation"