AP calculus MCQ

[thin wraith]

Why is the answer A? Can't it also be B?

[sullen bronze]

I think cuz the particle never moves higher than the origin
for (A), a < 0 and D < 0 so the graph always lie below the x-axis
for(B), a < 0 but D > 0 so there are times which the particle moves higher than the origin (x-axis), hence it's wrong

[thin wraith]

isn't the origin (0,0)?

or is it y=0

if its y=0 i understand the answer

[sullen bronze]

yes

[sullen bronze]

yes I assume it is

[thin wraith]

so by "reaches" the origin it doesnt mean touches 0,0? just means to be at the same vertical level of 0,0 which is y=0?

[sullen bronze]

it doesn't matter cuz the particle only moves along the y-axis

[thin wraith]

along the y axis means it is only ever negative or only ever positive?

[sullen bronze]

only ever negative or 0