Answer
C
Work Step by Step
$x=5\sin 38^{\circ}\implies \sin 38^{\circ}=\frac{x}{5}$
But $\sin\theta=\frac{\text{opposite side}}{\text{hypotenuse}}$
This implies that $x$ is the length of the opposite side to the $38^{\circ}$ angle and the length of the hypotenuse is 5. This is the case in triangle C.
