(A) : The production possibility Frontier can be a straight line.
(R) : The factors are not specialised and can be substituted at no extra cost.
1
Both (A) and (R) are true and (R) is the correct explanation of (A).
2
Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3
(A) is true, but (R) is false.
4
(A) is false, but (R) is true.