The Environmental Protection Agency frequently puts mandatory controls on toxic substances that present as little risk as one in a million chances to cause cancer.
A. as little risk as one in a million chances to cause
B. as little risk as one chance in a million of causing
C. as little risk as one chance in a million that it will cause
D. a risk as little as one chance in a million for causing
E. a risk as little as one chance in a million for it to cause

OA B . Why is A and D wrong ?