Final answer:
The amount that will vest immediately in Merrill's SIMPLE 401(k) plan is $1,200.
Step-by-step explanation:
In a SIMPLE 401(k) plan, the immediate vesting period for employer contributions is determined by the plan document. However, for Merrill's case, it is stated that his employer contributes 3% to the account. This means that the amount contributed by the employer will vest immediately, as there is no specified vesting schedule mentioned.
Therefore, the correct answer is b. $1,200.