GATE Computer Science (CS) 2011 Solved Paper

The following is the comment written for a C function.
/* This function computes the roots of a quadratic equation a.x∧2 + b.x + c = 0. The function stores two real roots in *root1 and *root2 and returns the status of validity of roots. It handles four different kinds of cases.
(i) When coefficient a is zero irrespective of discriminant
(ii) When discriminant is positive
(iii) When discriminant is zero
(iv) When discriminant is negative.
Only in case (ii) and (iii), the stored roots are valid. Otherwise 0 is stored in the roots. The function returns 0 when the roots are valid and -1 otherwise.
The function also ensures rootl >= root2.
int get_QuadRoots(float a, float b, float c,
float *root1, float *root2);
*/
A software test engineer is assigned the job of doing black box testing. He comes up with the following test cases, many of which are redundant.

Which one of the following options provide the set of non-redundant tests using equivalence class partitioning approach from input perspective for black box testing