Sec. 106. (a) If an item states that it is "payable through" a bank identified in the item:
(1) the item designates the bank as a collecting bank and does not by itself authorize the bank to pay the item; and
(2) the item may be presented for payment only by or through the bank.
(b) If an item states that it is "payable at" a bank identified in the item:
(1) the item designates the bank as a collecting bank and does not by itself authorize the bank to pay the item; and
(2) the item may be presented for payment only by or through the bank.
(c) If a draft names a nonbank drawee and it is unclear whether a bank named in the draft is a co-drawee or a collecting bank, the bank is a collecting bank.