Jerry agreed, in writing, to sublet his apartment to Kramer for $16$ months for $$4,000$ per month. After Kramer had been living in the apartment for $3$ months, Jerry and Kramer agreed, in writing, to amend the sublease so that the rent would be reduced to $$3,000$ per month provided Kramer picked up Jerry's mail every day. After the rent reduction modification, Jerry and Kramer agreed that Kramer could pick up the mail monthly rather than daily if he also watered Jerry's plants. Later Kramer found a cheaper apartment that was less hassle, so he reneged on the deal with Jerry and moved out. Jerry sued. Which is true?

Question $13$ options:

Both the original agreement and the rent reduction modification had to be in writing to be enforceable.

Jerry's agreement that Kramer could pick up the mail monthly rather than daily was supported by consideration.

The parol evidence rule did not bar Kramer from introducing evidence to show he was only required to pick up Jerry's mail monthly.

All of the above.

None of the above.