Answer:
"30 years or less when, in reality, the average age is more than 30 years"
Step-by-step explanation:
Type I error is produced when conclusion rejects a true null hypothesis.
The null hypothesis is
"The average gamer is more than 30 years old"
(deduced from the wording, not explicitly stated).
Then if the conclusion is "the average gamer is less than or equal to 30 years old" when in reality the average age is more than 30 years, then there is a type I error, since the null hypothesis is rejected.
Answer is D:
"30 years or less when, in reality, the average age is more than 30 years"