Which of the following statements is true?

The fully demethylated head of a-tocopherol increases its activity.

The fully demethylated head of a-tocopherol decreases its activity .

The fully methylated head of a-tocopherol increases its activity .

The fully methylated head of a-tocopherol decreases its activity.

The fully demethylated head of a-tocopherol decreases its activity.