13. It can reasonably be inferred from the passage that
before Harrison’s efforts, other individuals trying to
solve the longitude problem had failed to:
A. consider clocks as the potential instrument of calculation.
B. agree on why longitude decreases in value at
increasing distances from Earth’s equator.
C. improve upon the features of clocks that made
them unreliable at sea.
D. understand the ways that charts and compasses
could be used in connection with timepieces to