Two Years Ago, John, Then Aged 16, Entered into a Contract

Two years ago, John, then aged 16, entered into a contract with Jane, then aged 20. John has now turned 18 and wishes to be bound by the contract. Which of the following steps must he take in order to accomplish this? Please select all that apply.

A) John must ratify the contract.
B) John must provide fresh consideration.
C) John must get Jane to provide fresh consideration.
D) John does not need to do anything because the contract became automatically binding on him on his 18^th birthday.