If a golfer accidentally contacts the ball when addressing it, he is assessed a stroke according to the rules of golf. This counts towards his score for the hole, and the ball should be replaced without penalty if the incident occurs on the tee or elsewhere on the course before any stroke has been made.
If a golfer accidentally makes contact with the ball when addressing it, the proper ruling according to the rules of golf is that he is assessed a stroke. This means that the accidental contact counts as a stroke in the golfer's score for the hole. Notably, the specific application of this rule can vary depending on the version of the golf rules in play. The 2019 update to the Rules of Golf, implemented by the R&A and the USGA, changed how accidental movements of the ball on the putting green are treated. However, if a similar instance happens on the tee or elsewhere on the course, and the player accidentally moves their ball or ball-marker before a stroke has been made, the player should replace it without penalty.
Option A is correct: He is assessed a stroke. Options B, C, and D are incorrect. There is no applause for such an action, the golfer does not lose a turn, and the term used in golf is 'assessed a stroke' rather than 'scores a stroke' as scoring generally implies a positive action towards completing the hole.