Multi-choice problem: Choose from the options at the end, and answer how do you do this: To make a color of oil paint darker,

Choose from:
(a). squeeze equal amounts of the original color and a lighter color onto a palette, and mix them with a palette knife blade, adding more of either color to adjust the shade..
(b). squeeze equal amounts of the original color and a darker color onto a palette, and mix them with a palette knife blade, adding more of either color to adjust the shade..
(b).