SOH CAH TOA
Sine = opposite/hypotenuse
Cosine = adjacent/hypotenuse
Tangent = opposite/adjacent
The "slanted side" is also called the hypotenuse, and as we can see there is no such thing as the hypotenuse as the numerator, so using that alone we know the answer is D.
However, I will give you an explanation.
The opposite of an angle is the side that it is not touching at all, which in this case is the side with no name.
The hypotenuse is always the longest side, usually slanted (can be different because some images are turned.)
The adjacent is the 10 in side.
So using the formulas for sine, cosine, and tangent, none of these options would make sense. The only option that has the formula with its corresponding trig function is D.