The sentence which does not contain any
punctuation errors is:
<span><span>
A. </span><span>Waiting for my friends, I think that I arrived
too early. </span></span>
<span>
The sentence
is divided into dependent and independent clauses. The first clause is
dependent because it does not make sense and can’t stand alone without the
independent clause.</span>
I think it would be 'After drumming on his desk, Stewart was disciplined by Mrs. Hobson for distracting students from their exams.'
Ambiguous.
It will be an "ambiguous" ending.
