Which sentence contains an incorrect possessive form?

A. There's not a dimes worth of difference between the two models.

B. In those days, $20.00 for a day's work was a good wage.

C. My family took a week's vacation to the mountains.

D. How can you buy a dollar's worth of gas?

The sentence that contains an incorrect possessive form is A) There's not a dimes worth of difference between the two models.

If you want to show possession, you need to use an apostrophe.

The correct sentence would look like this: There's not a dime's worth of difference between the two models.