Which sentence below contains an incorrect verb form?
A.
The design of Marvel Comics' The Incredible Hulk is going through many changes since it was created by Stan Lee and Jack Kirby.
B.
Even though many are familiar with the character's green skin, the original character of the Hulk briefly had gray skin before it changed to the familiar green tone.
C.
David also gave the Hulk a change in attitude and personality as the one "big, d*mb behemoth" became a street-wise gangster nicknamed Mr. Fixit.
D.
Through the years, even though the color of the character has been consistently green, writer Peter David changed the Hulk's color to gray during the late 80s.