Read the following context and choose the best option to answer the question.
Context: Boy I ca nt believe this happened ! If I could turn around and kick myself i would lol ! I ' ve done it a million times without anything happening until ... on 7/25 I was unloading the truck and coming down from the liftgate with a cart full of oxygen tanks . Somehow the cart kept going right off the gate and took me with it .
Question: Why did the narrator lose control of the cart with the tanks on it ?
Options: 
A. None of the above choices .
B. The hot July sun caused the to become woozy .
C. The narrator slipped on the icy ground .
D. The tanks were heavy causing the cart pull away from the narrator .


D