To economists,
the main difference
between the short run
and the long run is that _____.

a. the law of decreasing
marginal returns applies
in the long run but
not in the short run.

b. in the short run,
all inputs are fixed
while in the long run
all inputs are variable.

c. fixed costs are more
important to decision
making in the long run
than they are in the short
run.

d. in the long run all
inputs are variable
while in the short
run at least one input
is fixed.

e. a and d.