This is in Differential Calculus. This is only multiple choice. Provide necessary solution for each items. Thank you and Godbless.

4. Given z= x + ysin(xy) -xy, find orz dy Ox ry . A) -x ysin(xy) + ycos(xy) - 1 C) -xy' sin(xy) + ycos(xy) - 1 B) -xy sin(xy) + 2ycos(xy) - 1 D) -xy sin(xy)+ 2ycos(xy)- 1 5. Given z=x'+ 2y'+6x -6xy - 3y , find Ox dy or z A) 12y -6 C) 6y -6 B) 6x -6 D) -6 6. Given z=x'+ 2v' +6x2 -6xy - 3y, find A) -6 C) 6y -6 B) 12v -6 D) 6x -6