Deaths by drowning at the state beach have increased by 35%

Deaths by drowning at the state beach have increased by 35% this year, due not to having less lifeguards but to dramatic changes in ocean currents.
(A) due not to having less lifeguards but to
(B) due not to having fewer lifeguards but
(C) because of not having less lifeguards but
(D) because it had not less lifeguards but
(E) not because it had fewer lifeguards but because it saw

Diction is one of the trickier topics on the GMAT SC. Find out more about it at this blog, which also includes a complete explanation of this question.
http://magoosh.com/gmat/2013/diction-on ... orrection/

Mike