Marabelle owns 100 Shares of stock of the Lindy Chocolate Corporation. She sells her stock to Dennis and delivers him: (1) her stock certificate for 100 shares and (2) a written, signed assignment of the 100 shares. The assignment form printed on the back of the share certificate is left blank and is not signed. Dennis refuses to take the certificate and the assignment on grounds that Marabelle must fill in and sign the assignment form. He is worried the ass t without it being filled out or signed, it will make the transfer of the stock invalid.

Is he correct? Why or why not?