The longer Adolph stayed on his job, the more he hated it$.$ He thought his boss was too demanding. He especially disliked being reprimanded for being late. One afternoon, he was asked by a secretary to take a letter to his boss for his signature. His boss had had an eye operation and was recuperating at home. Adolph got two signatures, one on the letter and one on a note promising to pay Adolph $$1000$ in consideration for services rendered. His boss was not careless, but couldn't read the papers. What plea or argument, if any, could his boss use to avoid paying on the promissory note?

Select one:

A$.$ Rectification

B$.$ Unconscionability

C$.$ Duress

D$.$ Non est factum

E$.$ Shared mistake