Lead Pipes Were Used at One Time for Delivering Drinking

Lead pipes were used at one time for delivering drinking water. What is the maximum possible concentration of lead in this water if it comes from lead(II) hydroxide (K_sp = 2.8 *10^-16) dissolving from the surface of the pipes? Note the U.S. Environmental Protection Agency's limit on lead in drinking water is 7.2*10^-8 M.

A) 4.1 * 10^-6 M
B) 1.6 *10^-8 M
C) 6.5 *10^-6 M
D) 5.1*10^-6 M
E) 8.3 F*10^-9 M