Final answer:
Competitive orienteering combines navigation and running, requiring competitors to use a map and compass to find checkpoints. Competitors receive a clue card at the start of the event and must have their cards marked at each checkpoint.
Step-by-step explanation:
Competitive orienteering is a sport that combines navigation and running. It involves using a map and a compass to navigate through a course and find checkpoints. Now, let's address each option:
- Competitors receive a clue card at the start of the event: This is true. Competitors are given a clue card that provides information about the locations of the checkpoints.
- Competitors leave the starting line at equal time intervals: This is false. In competitive orienteering, competitors usually start at different times to avoid crowding at the checkpoints.
- Competitors must have their cards marked at each checkpoint: This is true. When competitors find a checkpoint, they have their clue card marked to prove that they found it.
Considering the explanations provided, the correct answer is (a) Competitors receive a clue card at the start of the event and (c) Competitors must have their cards marked at each checkpoint.