Answer:
The correct options are 1 and 2.
Explanation:
Given information: A is the midpoint of SM.
It means point A divides the line segment SM in 2 equal parts.

From the given figure it is clear that the point S,A and M are collinear because they lie on a straight line. Using addition of segments we get

Since
and
are true. Therefore the correct options are 1 and 2.