The work done by the person against gravity is equal to the potential energy gained by the block. The formula for potential energy is $PE = mgh$, where $m$ is the mass, $g$ is the acceleration due to gravity, and $h$ is the height. Given: Mass ($m$) = 2 kg Height ($h$) = 5 m Acceleration due to gravity ($g$) = $10 \ m/s^2$ Work done ($W$) = $PE = mgh = 2 \times 10 \times 5 = 100 \ J$. Therefore, the work done by the person against gravity is 100 J. Options A, B, and D are incorrect as they do not match the calculated work done.