Which of the following is a correct statement as to 401(k) plans?

a. An employee who has completed a specified number of years of participation, as provided in the plan, may receive a distribution of funds from the plan which are attributable to elective deferrals.

b. An employee's right to other employee benefits may be conditioned on his participation in the employer's 401(k) plan.

c. A 401(k) plan must specify whether contributions will be received by employees in cash or contributed on their behalf to an account.

d. A 401(k) plan is subject to the minimum age and service, coverage, participation, and vesting requirements that are applicable to qualified plans.