Suppose There Are Only Two Goods Produced in Our Economy-Snowplows

Multiple Choice

Suppose there are only two goods produced in our economy-snowplows and helicopters.If there is always a two-for-one tradeoff between the production of these two goods (in terms of opportunity cost) ,then the production possibilities boundary between snowplows and helicopters is

A) a downward-sloping curve convex to the origin.
B) circular.
C) a downward-sloping straight line.
D) a downward-sloping straight line with slope equal to -1.
E) a downward-sloping curve concave to the origin.