Which statement best explains why using the completing the square method is the preferred strategy over using factoring and the quadratic formula?

• A. Completing the square is primarily useful only for checking answers from the quadratic formula and offers no advantage for graphing or when coefficients are fractions
• B. Completing the square should be used only when the discriminant is positive and yields rational square roots, because otherwise it cannot produce complex roots
• C. Completing the square is always the fastest method for finding integer roots and should be used before attempting factoring or using the quadratic formula in every problem
• D. Completing the square is preferable when you need the vertex form for graphing or when an exact expression for the vertex and roots is required, even if factoring is not available, because it transforms the quadratic into: $(x+c{)}^2+k$ and reveals the geometric information

Answer: (D)