Answer :
reference point is most often given a value of zero to describe an objects position.
Object's position on a straight line is given a value Zero
0=Starting point,or The origin,
From where the object move either to right or left on the straight line.
We can assign other values to starting point apart from zero, but giving value 0, to the object’s position on a straight line makes our calculation easier.
For example,
→x=0, to x=16
Distance traveled =16-0=16.
Do not need to do any calculation.
→x=1,to x=16
Distance traveled =16-1=15
the calculation needs to be done in second case.
So, assigning 0, to starting point is better option.