(i) is suitable for soils in which roof can stand for few minutes without support
(ii) is suitable for brick lining
(iii) is suitable for concrete lining
(iv) requires large number of trench jacks
select the answer?
A. only (i) is correct B. (i), (ii) and (iv) are correct
C. (i), (iii) and (iv) are correct
D. (i) and (ii) are correct