(A)
it must now be ascertained by the president's advisors how the country can both expand foreign trade and work effectively toward peace in the region, which they were unable to do in the past
"Having" in the non-underlines portion implies a possession and usually refers to animatic things. "it" is
INCORRECT(B)
it must now be ascertained by the president's advisors how the country can both
expand foreign trade and
must work effectively toward peace, which they were unable to do in the past in the region
"expand" and "must" are not parallel. This option also repeats the error in option A
INCORRECT(C)
the president's advisors must now ascertain
both how the country can expand foreign trade and work effectively toward peace in the region, which they were unable to do in the past
Wrong placement of the word "both"
INCORRECT(D)
the president's advisors must now ascertain how the country can both
expand foreign trade and
work effectively toward peace in the region, which they were unable to do in the past
(E)
the president's advisors must now ascertain how the country can
both expand foreign trade and
also how to make it work more effectively than in the past toward peace in the region
"both" and "also" are repetitive.
INCORRECTHence option D