Which of the following incidents might be considered a theft loss for tax purposes?

The disappearance of a diamond necklace, discovered on July 1. The last time the taxpayer remembers seeing the necklace was in February.

The accidental destruction of the taxpayer's car while his dependent daughter was driving it.

The loss of the taxpayer's wallet containing $1,000 cash, as a result of a mugging.

The theft of a cash-basis taxpayer's services. The taxpayer, a tutor, was not paid for $50 of tutoring classes.