Which of the following statement represent hydroponics? (i) Is useful in areas having thin; infertile and dry soils. (ii) Can regulate pH optimum for a particular crop. (iii) Increases labour cost. (iv) Increases problem of weeding.

• A. (i),(ii) and (iii)    
• B.        (i) and (ii)
• C.        (ii) and (iv)                    
• D.        (i) and (iii) .