Correct Answer: Blasphemy

Solution : The correct choice is the first option.

Blasphemy specifically denotes the action or offence of speaking sacrilegiously about God or sacred things, involving profane talk. It precisely matches the description provided in the given group of words.

The meanings of other options are as follows:

• Extempore means spoken or done without preparation; impromptu.
• Ephemeral means lasting for a very short time.
• A crusade is a vigorous campaign for political, social, or religious change.

Therefore, the correct answer is blasphemy.