"Douglas Pools Inc. operates a pool company in Toronto. In order to finance the business, Douglas Pools negotiated a line of credit with the Bank of Montreal to a maximum indebtedness of $300,000. The line of credit was secured by a general security agreement in favour of the bank, in which the collateral is described as "all assets of Douglas Pools, all after-acquired property and proceeds thereof." The bank registered its security interest under the PPSA on January 10, 2011. On March 30, 2011, Douglas Pools bought a 2009 Dodge Ram pick-up truck from London Dodge for $15,000. London Dodge agreed to accept payment for the truck over three years, with interest at 6% per year, and took a security interest in the truck in order to secure payment of the purchase price. London Dodge registered its security interest under the PPSA on April 4, 2011. On November 11, 2011, Douglas Pools sold the truck to Fisher & Co. (a company owned by the same person that owns Douglas Pools) for $1.00. Douglas Pools defaulted on its obligations to both the bank and London Dodge and, on November 18, 2011, declared bankruptcy. At the time of the bankruptcy, Douglas Pools owed the bank $240,000 and London Dodge $12,000. Now, the bank, London Dodge, the trustee in bankruptcy, and Fisher & Co. all claim the truck. Whose claim to the truck has first priority? Whose claim has second priority?"

In this case, London Dodge would have first priority because of PMSI, please specify what is PMSI, why does London Dodge have it, why the other parties do not have it?