For this case we have to define trigonometric relationships of rectangular triangles, that the sine of an angle is given by the opposite leg to the angle on the hypotenuse of the triangle. That is to say:
[tex]Sin (51)=\frac {CB} {58}\\CB=Sin (51) * 58\\CB=0.777 * 58\\CB =45.07[/tex]
Answer:
Option A