Amount of net purchase can be calculated as follow:

(A) Purchase of direct material add trade discount less purchase return add carriage inward less other material handling cost
(B) Purchase of direct material less trade discount l add purchase return add carriage inward less other material handling cost
(C) Purchase of direct material less trade discount less purchase return less carriage inward add other material handling cost
(D) Purchase of direct material less trade discount less purchase return add carriage inward add other material handling cost