Which of the following is correct regarding the issue of discrimination in a collective agreement?

a.Because human rights legislation protects against discrimination most collective agreements do not contain terms relating to discrimination.

b.The parties can agree that the protection provided in human rights legislation against discrimination on the basis of age does not apply so that mandatory retirement is permissible.

c.Human rights legislation protects employees against discrimination because of union activity.

d.The parties can provide for a higher level of human rights protection in the collective agreement than human rights legislation requires.