In recent years, there have been thousands of refugees from countries as diverse as Cambodia and Haiti who
had chosen the risk of death at sea rather than endure the certainty of poverty and oppression at home.A) had chosen the risk of death at sea rather than endure
The use of past perfect when there is only one past event is wrong. Wrong.
B) had chosen the risk of death at sea instead of enduring
Same as A. Wrong
C) have chosen risking death at sea instead of enduring
Instead of is used mostly to show replacement. Rather than is to show preference. In most cases, "rather than" is preferred over "instead of" in GMAT.
Also instead of + "preposition" is correct. Here it is a gerund. Wrong
D) have chosen to risk death at sea rather than enduring
to risk not parallel with enduring. Wrong
E) have chosen to risk death at sea rather than endure
to risk || to endure. (ellipses in the play here!) Right!