Answer:
The correct option is (B).
Step-by-step explanation:
A type-I-error occurs when we discard a true null-hypothesis (H₀).
The hypothesis in this case are:
H₀: The proportion of Americans that have seen a UFO is 0.002, i.e. p = 0.002.
Hₐ: The proportion of Americans that have seen a UFO is less than 0.002, i.e. p < 0.002.
A type I error will be committed, if we reject the claim that the proportion of Americans that have seen a UFO is equal to 2 in a thousand when that proportion is actually 2 in a thousand.
The correct option is (B).