This is another one that I got wrong and here is my explanation on why the answer is B:
A - clearly wrong since we are given statements which all lead to the conclusion. The evidence is not suppose to be viewed by itself but rather the evidence works together to contribute to the conclusion.
B - this one is tricky but is the correct answer. Rephrasing this answer to use the stimulus, we get, establishing that Thomas saw the fire by showing that ABC occurred (fire-fighters did not leave until late afternoon and no one could have been near the fire and not seen it) by showing that ABC (mentioned above) occurred is enough too show that Thomas saw the fire. The stimulus was giving us conditions which were sufficient to show that the fire occurred which is the relationship described in this answer.
C - wrong there is no mention of why the view held by someone would be tempting.
D - wrong no mention of events in the past.
E - wrong we do not get any support to say the evidence is first hand, for all we know the author heard this on the news and actually was not at the vicinity of the fire.