Answer:
Option (2) and (4) are correct.
and
are points on the unit circle.
Step-by-step explanation:
Given : Some points of circles.
We have to choose which points could be points on the unit circle.
We know, the equation of circle is
..........(1)
where r is radius of circle.
We check each point for x and y values on the equation of circle and see which point gives radius = 1
Thus,
1) 
Put in LHS of (1) , we have,

Simplify, we have,


Thus,
is not a point on the unit circle.
2) 
Put in LHS of (1) , we have,

Simplify, we have,


Thus,
is a point on the unit circle.
3) 
Put in LHS of (1) , we have,

Simplify, we have,


Thus,
is not a point on the unit circle.
4) 
Put in LHS of (1) , we have,

Simplify, we have,


Thus,
is a point on the unit circle.
Thus,
and
are points on the unit circle.