Still, the storm surge was both stronger and earlier than expected, apparently coming through waterways southeast of the city, said Col. Richard Wagenaar, the Army Corps of Engineers' district chief in New Orleans.
Can we infer the following?
Even though the storm surge was both stronger and earlier than expected, it was not certain that it all came from the southeast. 

Options are:
[a]. Yes;
[b]. It's impossible to say;
[c]. No;
The answer is: