C is on the line segment AB, but we cannot conclude that C is on the perpendicular bisector of segment AB without additional information.
The only information we have about the diagram is that C is a point on the line segment AB.
We do not know if the line segment AB is divided into two equal segments by point C, or if the line segment AB is perpendicular to the line segment CD.
In order to conclude that C is on the perpendicular bisector of segment AB, we would need to know one of the following:
The line segment AB is divided into two equal segments by point C.
The line segment AB is perpendicular to the line segment CD.
Both of the above conditions are met.
Without this additional information, we cannot conclude that C is on the perpendicular bisector of segment AB.
Here are some examples of diagrams where the information is not enough to conclude that C is on the perpendicular bisector of segment AB:
A diagram of a square, with C at the midpoint of one of the sides of the square.
A diagram of a rhombus, with C at the point of intersection of the diagonals of the rhombus.
A diagram of a right triangle, with C at the midpoint of the hypotenuse of the triangle.