Explanation

This applies Vieta's formulas to px² + 3x + 2q = 0: the sum of the roots is −3/p and the product is 2q/p. Both are given as −6, so −3/p = −6 gives p = 1/2, and 2q/p = −6 gives 2q/(1/2) = 4q = −6, i.e. q = −3/2. Then p − q = 1/2 − (−3/2) = 2. Hence option (c). The distractors −1 and 1 arise from sign errors in the product relation (taking q = +3/2 or mishandling the minus in p − q).