John drew rhombus RSTV. He drew both diagonals that intersect at point M. in johns figure, which would be the measure of RMS -45°
-90°
-180°
-360°

Option B

Step-by-step explanation:

One of the  basic property of Rhombus is that its diagonal intersect each other in a way that they bisect each other and also make angle of 90 degrees

Angle RMS comprises of angle formed by the bisecting diagonals. Hence angle RMS is of 90 degrees.

Thus, option B is correct