I dont understand the following exercise:

20. Refer to the data in the table below, which shows various methods of producing a given volume of output, to answer the questions below.

Method Capital Labour Output

A 5 12 100

B 8 15 100

C 7 10 100

The prices of capital and labour are $5 and $10 respectively. If the prices of capital and labour were reversed:

a.method B would be technically efficient

b.method C would be technically inefficient

c.method B would be economically efficient

d.method A would be economically efficient