maths help

a diagram shows the (exponential)graph of y=3e^kx. the graph goes through the points (0,3) and (4,18). what is the value of k? is it: a)3/2e b)1/4 log(smalle)6 c) 1/4 log(smalle)15 d) 1/18 log(smalle)4/3 could you please go over the working because i have...