18. There are fundamentally two possible changes in an economy that will each cause inflation unless other compensating changes also occur. These changes are either reductions in the supply of goods and services or increases in demand. In a prebanking economy the quantity of money available, and hence the level of demand, is equivalent to the quantity of gold available.

If the statements above are true, then it is also true that in a prebanking economy

(A) any inflation is the result of reductions in the supply of goods and services

(B) if other factors in the economy are unchanged, increasing the quantity of gold available will lead to inflation

(C) if there is a reduction in the quantity of gold available, then, other things being equal, inflation must result

(D) the quantity of goods and services purchasable by a given amount of gold is constant（B）

(E) whatever changes in demand occur, there will be compensating changes in the supply of goods and services

为什么是b呢，我怎么觉得是C? 需求多，或者供应少，都将引起inflation. 那么如果gold少了，就是供应少了，就会有inflation呀。