Crouch operates a construction service. On June 1, Crouch purchased a new bulldozer for business use on credit from Digger Depo ("Digger"). Pursuant to the written credit agreement, Digger retained title in the bulldozer until full payment was made. Digger filed no financing statement. Which one of the following statements is true?

1. Digger has no security interest in the bulldozer; Digger simply retained title and ownership until Crouch made full payment.

2. Digger has an unperfected security interest in the bulldozer.

3. Digger has an automatically perfected purchase-money security interest in the bulldozer.

4. Digger has a security interest in the bulldozer that is not a purchase-money security interest.