If the radius of a right circular cylinder open at both the ends, is decreased by 25% and the height of the cylinder is increased by 25%. Then the curved surface area of the cylinder thus formed
यदि किसी लंब वृत्तीय बेलन, जो किनारों पर खुला है, की त्रिज्या 25% कम कर दी जाए ओर उसको ऊँचाई 25% बढ़ा दी जाए तो इस प्रकार बने बेलन का वक्र पृष्ठ क्षेत्रफल कैसा होगा?

Options

A. remains unchange
B. is increased by 25%
C. is increased by 6.25%
D. is decreased by 6.25%