What is the taxpayer's gross income in each of the following situations?

a. Darrin received a salary of $50,000 in 2015 from his employer, Green Construction.

b. In July 2015, Green gave Darrin an all-expense-paid trip to Las Vegas (value of $3,000) for exceeding his sales quota.

c. Megan received $10,000 from her employer to help her pay medical expenses not covered by insurance.

d. Blake received $15,000 from his deceased wife's employer "to help him in his time of greatest need."

e. Clint collected $50,000 as the beneficiary of a group term life insurance policy when his wife died. The premiums on the policy were paid by his deceased wife's employer.