A student is pushing a box of mass M on a frictionless surface. Another box of mass M is then placed on the first box. Which of the following describes the acceleration of the boxes?
Select one:
A. The velocity is constant.
question
B. The boxes slow down.
C. The acceleration remains the same.
D. The acceleration doubles.
E. The acceleration is halved.

ι вєℓιєνє ιт ιѕ тнє fιяѕт ¢нσι¢є(α.)

нє ѕнσυℓ∂ ѕмιℓє ρσℓιтℓу αи∂ ѕρєαк тσ тнє ρєяѕσи ωнσ ιѕ ιитєяяυριиg αfтєя тнє ∂ιѕ¢υѕѕισи

нσρє ι ¢συℓ∂ нєℓρ.

the entire statement is true and correct.  

there's no diagram, nothing is illustrated, and no question is asked.

one "light year" is the distance that light travels, through vacuum, in one julian year.   that's 365.25 days, of 24 hours each.