Final answer:
The correct playwriting exercise to begin crafting dialogue is writing a monologue, which helps develop vital dialogue skills necessary for a character's speech in a play.
Step-by-step explanation:
The correct answer to the question of one playwriting exercise to begin crafting dialogue is C) Writing a monologue. This exercise helps playwrights develop the skill of writing speech for characters, which is a crucial element of a play.
Because plays rely on dialogue and stage directions to tell a story and convey characters' thoughts and feelings without the aid of a narrator, crafting strong dialogue through exercises like writing monologues is a foundational skill for playwrights. Writing a monologue allows the playwright to delve deeply into a character's perspective and voice, which can later be expanded into dialogue between characters.