Verify Property 2 of the definition of a probability density function over the given interval. f(x)=9e-9x [0,00) What is Property 2 of the definition of a probability density function? A. The area under the graph of f over the interval [a,b] is a. B. The area under the graph of f over the interval [a,b] is 1. C. The area under the graph of f over the interval [a,b] is b. Since the given interval, [0,co), has a right-endpoint of infinity, the area under the graph of f will be calculated using an improper integral. Choose the correct formula for an improper integral over the interval [a,co] below. A. 0 B. S f(x) dx = lim 800+9 f(x) dx = lim [F(x)] = lim (F(a) - F(b)) b Sf(x) d a b f(x) dx= lim Sf(x) dx =_ 00+9 b