An individual is required to perform a discrete, open and externally paced skill - HSC - SSCE Personal Development and Physical Education - Question 2 - 2015 - Paper 1

To evaluate which skill meets the criteria of being discrete, open, and externally paced, we can analyze the options:

1. Putting in golf - This is a discrete skill as it has a defined beginning and end, but it is not typically an externally paced skill; the pace is often controlled by the player.

2. Running 800m - This activity is continuous and not discrete, making it unsuitable.

3. Throwing a discus - This is a discrete skill, but like putting, it is generally not open since it has a set environment and conditions.

4. Returning a tennis serve - This is a discrete skill that occurs in a dynamic and open environment, as the player must react to incoming serves and perform the skill under varying conditions. It also aligns with being externally paced as the opponent controls the timing of the serve.

Thus, the best answer is (D) Returning a tennis serve.