Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is not the correct explanation of A.

A is true but R is false.

A is false but R is true.

(i) and (ii) are correct

(i) and (iii) are correct

(ii) and (iii) are correct

(i), (ii) and (iii) are correct

1 alone is correct

2 alone is correct

both 1 and 2 are correct

neither 1 nor 2 is correct

0.4 kg/cm2

0.7 kg/cm2

1.0 kg/cm2

1.2 kg/cm2

providing buttresses at certain intervals

providing a deeper foundation

using a richer mortar

using stronger bricks