Stoven, who owned Craigmont in fee simple, mortgaged Craigmont to Ulrich to secure a loan of $100,000. The mortgage was promptly and properly recorded. Stoven later mortgaged Craigmont to Martin to secure a loan of $50,000. The mortgage was promptly and properly recorded. Subsequently, Stoven conveyed Craigmont to Fritsch. About a year later, Fritsch borrowed $100,000 from Zorn, an elderly widow, and gave her a mortgage on Craigmont to secure repayment of the loan. Zorn did not know about the mortgage held by Martin. The understanding between Fritsch and Zorn was that Fritsch would use the $100,000 to pay off the mortgage held by Ulrich and that Zorn would, therefore, have a first mortgage on Craigmont. Zorn's mortgage was promptly and properly recorded. Fritsch paid the $100,000 received from Zorn to Ulrich and obtained and recorded a release of the Ulrich mortgage. The $50,000 debt secured by the Martin mortgage was not paid when it was due, and Martin brought an appropriate action to foreclose, joining Stoven, Fritsch, and Zorn as defendants and alleging that Martin's mortgage was senior to Zorn's mortgage on Craigmont. If the court rules that Zorn's mortgage is entitled to priority over Martin's mortgage, which of the following determinations are necessary to support that ruling? I. Ulrich's mortgage was originally senior to Martin's mortgage. II. Zorn is entitled to have Ulrich's mortgage revived for her benefit, and Zorn is entitled to be subrogated to Ulrich's original position as senior mortgagee. III. There are no countervailing equities in favor of Martin. 
I and II only. I and III only. II and III only. I, II, and III. 