Time period of pendulum is given by
[tex]T = 2\pi\sqrt{\frac{L}{g}}[/tex]
Here,
L is length
g is acceleration due to gravity
Therefore we can determine that the period of the pendulum is directly proportional to the square root of the length of the rope.
[tex]T \propto \sqrt{L}[/tex]
Therefore, it is necessary to increase the length of the rope to increase the period so that it counts the seconds more slowly. The correct answer is A.