Find the points on the curve y=3x4+2x3-1 at which the tangents is parallel to the x-axis.

• A. (0,1) and \((-\frac{1}{2},-\frac{15}{16})\)
• B. (0,-1) and \((-\frac{1}{2},-\frac{15}{16})\)
• C. (0,-1) and \((\frac{1}{2},-\frac{15}{16})\)
• D. (0,1) and \((\frac{1}{2},\frac{15}{16})\)