Which of the following estate planning documents - will, codicil, letter of last instructions, living will - do the following individuals/families need? Explain your rationale.

a. Kayla, a recent college graduate with only a few personal assets, all jointly owned with her parents.

b. Justin and Edee, a couple in their 30s with two young children. They already have a will that they made when they were first married 10 years ago - before they had their second child.

c. Mac, a widowed man living with a close friend to whom he would like to leave his personal assets upon death.