Rash; Stoic

Rash means acting without thinking, whereas Stoic refers to someone who remains calm and unemotional. These words are opposites in nature.

A) "Articulate" means well-spoken, and an "Orator" is a public speaker. These words are related but not opposites.

B) "Dubious" means doubtful or suspicious, while "Scoundrel" means a dishonest person. They are not contrasting like "Rash" and "Stoic".

C) "Dolorous" means full of sorrow or grief. "Spouse" refers to a husband or wife. There is no direct opposition between the two.

D) An Agnostic doubts religious beliefs, while a Cleric is a spiritual leader. These two are contrasting, like "Rash" and "Stoic".

Hence, Option D is the correct answer.