3. Let F be an arbitrary function. Using the method of characteristics, the solution of the following PDE (y + u)uz + yuy = I - y, is (a) F(z 214, u) = 0 3+4 , ( 1 -y ) ?) =0 ( b) F. (C) F(zu W. (1 - y)2 - 12) = 0 (d) Fu 4, u) = 0