The maximum harbour depth below lowest low water is generally equal to_________________?

(i) loaded draft + 1.2 m when bottom is rock
(ii) loaded draft + 1.8 m when bottom is soft
(iii) loaded draft + 1.2 m when bottom is soft
(iv) loaded draft + 1.8 m when bottom is rock
select the correct the correct statements.
A. (i) and (ii) are correct
B. (i) and (iii) are correct
C. (ii) and (iv) are correct
D. (iii) and (iv) are correct