Baurer purchased a White Freightliner tractor and agreed that his son-in-law, Britton, could use it in the trucking business. In return, Britton agreed to haul Baurer’s hay and cattle, thus saving Baurer approximately $30,000 per year. Baurer insured the vehicle with Mountain West Farm Bureau Insurance Company. The policy contained an exclusionary clause that provided: “We don’t insure your [truck] while it is rented or leased to others.. This does not apply to the use of your [truck] on a share expense basis.” When the vehicle was destroyed, Mountain West refused to pay on the policy, contending that the arrangement between Baurer and Britton was a lease of the vehicle, which was excluded under the policy. Baurer sued, contending that it was a “share expense basis” allowed under the policy. Is the insurance policy ambiguous? What rule of contract construction applies in this case? Decide. [Baurer v Mountain West Farm Bureau Ins., 695 P2d 1307 (Mont)]