My best guess is A There is missing a time unit in the question. I know that 4.4 *5 = 21 so that would be my best guess.
By testing it out. Try it.
The acceleration of the first block (4 kg) is -9.8 m/s².
The given parameters:
- <em>Mass of the first block, m₁ = 4.0 kg</em>
- <em>Mass of the second block, m₂ = 2.0 kg</em>
The net force on the system of the two blocks is calculated as follows;

where;
- <em>T </em><em>is the tension in the connecting string due weight of the first block</em>

Thus, the acceleration of the first block (4 kg) is -9.8 m/s².
Learn more about net force on two connected blocks here: brainly.com/question/13539944
Pretty sure it’s C. all the others are speeding up. acceleration means gradually (over time) getting faster. So it’s C.