T is the only one given that fits according to the following.
The ampersand can be traced back to the 1st century A.D. and the Old Roman cursive, in which the letters E and T occasionally were written together to form a ligature (Evolution of the ampersand - figure 1). In the later and more flowing New Roman Cursive, ligatures of all kinds were extremely common; figures 2 and 3 from the middle of 4th century are examples of how the et-ligature could look in this script. During the later development of the Latin script leading up to Carolingian minuscule (9th century) the use of ligatures in general diminished. The et-ligature, however, continued to be used and gradually became more stylized and less revealing of its origin