Explain why each of the following is or is not

Explain why each of the following is or is not a valid probability distribution for a discrete random variable x:
a.
Explain why each of the following is or is not

b.

Explain why each of the following is or is not

c.

Explain why each of the following is or is not

d.

Explain why each of the following is or is not
Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...