Let P be a digital put struck at K1 and C be a digital call struck at K2. (A digital put pays 1 if spot is below the strike at expiry, and a digital call pays I if spot is above the strike.) What can we say about the prices of C and P in each of the following cases?
(i) K1 = K2;
(ii) K1 2;
(iii) K1 > K2.