The diaphragm is another term for the aperture, so it controls the amount of light passing into the film camera.
I'd say that the type of context clue that helps you understand the meaning of the word repining is B. restatement.
If the word is in the middle of the poem, you wouldn't want an explanation or an example, but its synonym in order to understand what that particular word means. At least that is what I believe, I'm sorry if you get this answer wrong. :/
The artwork is anonymus and it's titled as <span>Saint Anthony Leaving His Monastery Master of Osservanza
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Means to: Repeat the precedig music.
