While drawing a perpendicular to a given line through a point nearer to the end of the line, which of the following properties of the circle is used?

• A. The diameter of a circle always subtends an angle of 90 on the circumference
• B. The angle at the circumference is half the angle at the centre of the circle
• C. The summation of the opposite angles of a quadrilateral is always 180
• D. In an arc the angle subtended by any two points on the circumference is always same