Which of the following statements are correct?

I. In order for transfers to a QDOT to qualify for the unlimited marital deduction, the executor of a citizen spouse's estate must elect to have the marital deduction apply.

II$.$ A distribution to a surviving spouse of the principal of a QDOT will be subject to estate tax.

III. To be valid, a disclaimer must be filed within nine months of the decedent's death.

IV$.$ When a disclaimer is used, the property will pass to the person chosen by the disclaiming party.

Question $9$ options:

I, II$,$ and III only

II$,$ III, and IV only

I, II$,$ and IV only

I, II$,$ III, and IV