Rule 15-1 states a player must
hole out with the ball played from the teeing ground
. Additionally, Decision
27-10 provides guidance when there are two balls with identical (or no
distinguishable) markings are found in the same area. [ Did Player A play a
stroke with his original ball? There is a 50/50 chance that he did somewhat
less than meeting the requirement of must.] Also, see Decision 12-2/1.
Player A has played a wrong ball, incurring a two-stroke penalty, and must return to where he last played under a penalty of stroke and distance - total penalty of three strokes.