You put me in a difficult position. I can't help it, but the "sample answer" is by far the best way to explain this, briefly and correctly. There's no other choice but to copy it.
This is a short circuit. The branch without the bulb has almost no resistance, so all the current will flow through that branch instead of flowing through the bulb.
<em>If</em> the lower switch were <u>opened</u>, THEN we would have a series circuit. Current would no longer have any other choice but to flow through the bulb, and the bulb would light.
Sample Response: The lightbulb will not light because this is a short circuit. The branch without the bulb has almost no resistance, so all the current will flow through that branch instead of flowing through the bulb.
