Chronic low-level leaking and the routine discharge of

2. Chronic low-level leaking and the routine discharge of drilling mud and mineral salts present considerable environmental risk during offshore oil drilling.
(A) Chronic low-level leaking and the routine discharge of drilling mud and mineral salts present considerable environmental risk during offshore oil drilling.
(B) The reason offshore oil drilling presents a considerably environmental risk is because of chronic low-level leaking and the routine discharge of drilling mud and mineral salts.
(C) A considerable risk to the environment is presented during offshore oil drilling, where low-level leaks are chronic and the routine discharge of mud and mineral salts.
(D) Offshore oil drilling presents a considerable risk to the environment due to the fact of chronic low-level leaks, and mud and mineral salts are routinely discharged.
(E) Chronic low-level leaking, along with the routine discharge of drilling mud and mineral salts, are what make offshore oil drilling environmentally risky.