A particle of mass `m` moves on the ` x- axis ` as follows : it starts from rest at ` t = 0`, from the point `x = 0`, and comes to rest at ` t = l` at the point `x = 1`. No other information is available about its motion at intermediate times `( 0 lt t lt l)` . If `alpha ` denotes the instantaneous accelartion of the particle , then :
A. `alpha` cannot remain positive for all t in the interval `o le t le 1`
B. `|alpha|` cannot exceed 2 at any point in its path
C. `|alpha|` must be `ge 4` at some point or points in its path
D. `alpha` must change sign during the motion, but no other assertion can be made with the information given
