The answer to this question is C - the common error in this sentence is a
dangling modifier. The dangling modifier included here, would be the
words 'having risen'. It Is unclear in this sentence whether this phrase
is referring to the hikers, or the river. The hikers could have been
woken up early because of the rains, until we reach the end of the
sentence that concerns a river that also could have risen due to the
rains.
