Figure RHOM is a rhombus. Line segment R O and Line segment H M are the diagonals of the rhombus, as well as angle bisectors of the vertex angles, and they create four isosceles triangles: HOM, MHR, RHO, and OMR. Rhombus R H O M has all equal side lengths. Lines are drawn from each point to point S at the center.

What is true about AngleMSR?

a. It must be acute.
b. It must be a right angle.
c. It must be equal to AngleMRH.
d. It must be equal to AngleRMS.