When plotting a 2D function on $x-y$ plane, should I draw the arrowheads on the axes (Fig. A) or not (Fig. B)?
Are both ways considered correct?
Is there any occasion in which one is preferred than the other?
Or it is just a matter of style (and that we only need to be consistent with our choice)?
The arrows are superfluous, are not needed, and in fact some of the best calculus books on the market don't use them at all.