Triangle in Rectangular Cartesian Coordinates

Q.

How many vertices does a triangle have?

1. 6
2. 2
3. 4
4. 3

Q. Let $A(h,k),B(1,1)$ and $C(2,1)$ be the vertices of a right angled triangle with $AC$ as its hypotenuse. If the area of the triangle is 1 square unit, then the set of values which ${}^{\prime }{k}^{\prime }$ can take is given by

1. {$-1,3$}
2. {$-3,-2$}
3. {$1,3$}
4. {$0,2$}