§ 503. Venue based on residence. (a) Generally. Except where otherwise prescribed by law, the place of trial shall be in the county in which one of the parties resided when it was commenced; or, if none of the parties then resided in the state, in any county designated by the plaintiff. A party resident in more than one county shall be deemed a resident of each such county. (b) Executor, administrator, trustee, committee, conservator, general or testamentary guardian, or receiver. An executor, administrator, trustee, committee, conservator, general or testamentary guardian, or receiver shall be deemed a resident of the county of his appointment as well as the county in which he actually resides. (c) Corporation. A domestic corporation, or a foreign corporation authorized to transact business in the state, shall be deemed a resident of the county in which its principal office is located; except that such a corporation, if a railroad or other common carrier, shall also be deemed a resident of the county where the cause of action arose. (d) Unincorporated association, partnership, or individually-owned business. A president or treasurer of an unincorporated association, suing or being sued on behalf of the association, shall be deemed a resident of any county in which the association has its principal office, as well as the county in which he actually resides. A partnership or an individually-owned business shall be deemed a resident of any county in which it has its principal office, as well as the county in which the partner or individual owner suing or being sued actually resides. (e) Assignee. In an action for a sum of money only, brought by an assignee other than an assignee for the benefit of creditors or a holder in due course of a negotiable instrument, the assignee's residence shall be deemed the same as that of the original assignor at the time of the original assignment. (f) Consumer credit transaction. In an action arising out of a consumer credit transaction where a purchaser, borrower or debtor is a defendant, the place of trial shall be the residence of a defendant, if one resides within the state or the county where such transaction took place, if it is within the state, or, in other cases, as set forth in subdivision (a).