Ignoring warming up and cooling down before a workout can have several negative consequences for an individual. The correct answer is option 'C': They will increase the risk of injury, pain, and fatigue. Let's explore this in detail.

1. Importance of Warming Up:
- Warming up before a workout is crucial as it prepares the body for physical activity.
- It helps to gradually increase the heart rate, blood flow, and body temperature, which in turn improves muscle function and flexibility.
- Warm-up exercises such as jogging, stretching, or dynamic movements prepare the muscles, tendons, and ligaments for the upcoming workout.
- It also helps to mentally prepare for the workout, increasing focus and concentration.

2. Benefits of Warming Up:
- Improved muscle performance: Warming up increases blood circulation, delivering oxygen and nutrients to the muscles. This improves muscle performance, strength, and endurance during the workout.
- Enhanced flexibility: Warm-up exercises increase muscle and joint flexibility, reducing the risk of strains and sprains.
- Injury prevention: By gradually increasing the intensity of exercise, warm-up exercises prepare the body for the demands of the workout. This reduces the risk of muscle tears, strains, and other injuries.
- Increased range of motion: Proper warm-up exercises improve joint mobility, allowing for a wider range of motion during the workout.
- Mental preparation: Warming up helps to shift focus from daily activities to the workout, improving concentration and enhancing workout performance.

3. Consequences of Ignoring Warming Up:
- Increased risk of injury: Without a warm-up, the muscles and joints are not adequately prepared for the demands of the workout. This can lead to muscle strains, sprains, and other injuries.
- Decreased performance: Without a proper warm-up, the body may not be able to perform at its optimal level. This can result in reduced strength, endurance, and overall performance during the workout.
- Decreased flexibility: Skipping warm-up exercises can lead to decreased flexibility, limiting the range of motion and increasing the risk of injuries.
- Increased fatigue: Without a warm-up, the body may experience premature fatigue, which can reduce the effectiveness of the workout and lead to decreased motivation.

In conclusion, ignoring warming up before a workout can have detrimental effects on an individual's body. It increases the risk of injury, pain, and fatigue. Therefore, it is crucial to prioritize warming up before engaging in any physical activity to ensure a safe and effective workout.