One of the biggest challenges for the exploration and future colonization of space is the expense of launching materials from Earth. Current rocket propulsion technology makes launches very expensive. Every item launched into space must be considered carefully because the expense goes up with every extra pound of cargo.

This problem would be best solved with
A.
heavier, more durable rockets and launching methods that are less cost-efficient.
B.
launching methods that are more cost-efficient and cargo made of lighter materials.
C.
heavier, more durable rockets and launching methods that are more cost-efficient.
D.
launching methods that are more cost-efficient and cargo made of heavier materials.