Having finally reached a tentative labor agreement with its company's pilots,
it must now be determined by the airline's board of directors how the airline can both increase profits and compete more effectively for customers than they did in the past.(A) it must now be determined by the airline's board of directors how the airline can both increase profits and compete more effectively for customers than they did in the past
(B) it must now be determined by the airline's board of directors how the airline can both increase profits and must compete more effectively than in the past for customers
(C) the airline's board of directors must now determine both how to make the airline increase profits and compete more effectively for customers than they did in the past
(D) the airline's board of directors must now determine how the airline can both increase profits and compete more effectively for customers than it did in the past
(E) the airline's board of directors must now determine how the airline can both increase profits and also how to make it compete more effectively than in the past for customers
(C) the airline's board of directors must now determine both how to make the airline increase profits and compete more effectively for customers than they did in the past
(D) the airline's board of directors must now determine how the airline can both increase profits and compete more effectively for customers than it did in the past
(E) the airline's board of directors must now determine how the airline can both increase profits and also how to make it compete more effectively than in the past for customers
Who "Having finally reached a tentative labor agreement with its company's pilots" modifies? the airline's board of directors. So the subject must follow the comma: out A B.
In C both is misplaced, so we can eliminate this option. The correct idom is "both X and Y" not "both X and also Y", D wins: it also more clear and coincise then E.