Final answer:
When playing golf, after the first stroke outside of the teeing area, tee-markers are considered to be part of the course, and therefore, they are neither removed nor treated as obstructions.
Step-by-step explanation:
In the game of golf, tee-markers are treated differently depending on where they are located. When a player is hitting from the teeing area, the tee-markers define the area within which the player must tee the ball. However, once the player has made their first stroke and is playing the ball from the course, the treatment of tee-markers changes. Outside of the teeing area, tee-markers are regarded as fixed objects, similar to the wording in option (b) they are played as part of the course. Therefore, one does not remove the tee-markers nor are they considered immovable obstructions. The fact that they are ignored during play after the teeing area also implies their status as part of the course, thus providing a rationale for why the markers are not treated as obstructions.