If a plane meets the coordinate axes at the points (a, 0, 0), (0, b, 0) and (0, 0, c), then its equation is
x/a + y/b +z/c = 1
(i) A plane cuts the coordinate axes at A(2, 0, 0), B(0, 3, 0) and C(0, 0, 1). Then the area of the triangle ABC is
(A) 11/2
(B) 9/2
(C) 7/2
(D) 5/2
(ii) The volume of the tetrahedron OABC, where O is the origin, is
(A) 6
(B) 1
(C) 2
(D) 1 6
(iii) The centroid of tetrahedron OABC is
(A) 1/2,3/4,1/4
(B) 1/4,3/4,1/4
(C) 2/3,1,1/3
(D) 1/3,1/3,1/3