It is impossible for an ordinary mortal to . . . . . . . . all these figures to memory.

The correct answer is C. retain.

To retain something means to keep it in one’s mind or memory. In this case, it is impossible for an ordinary mortal to keep all these figures in their memory.

The other options are not as accurate.

• Keep can
  Join Our Telegram Channel
  48.6-11.4 42.9-11.4 132.3-11.4 132.3s0 89.4 11.4 132.3c6.3 23.7 24.8 41.5 48.3 47.8C117.2 448 288 448 288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube