Which choice best introduces the topic of this
sentence?
A) NO CHANGE
B) The EPA can only regulate a new chemical if it can
prove that the chemical poses "unreasonable risk,"
but
C) Because there is controversy over which tests can
best determine whether a chemical is safe,
D) It's hard to know whether the lack of regulation
is more the fault of the TSCA, or the EPA itself
needs reform, and
