Wireless-N behind two walls

This is interesting. My friend placed a PC at the reception area, and this is like two walls away from the router and its like 15-18metres.

U guys make a guess, what sort of speed and quality you will get:-

a) 11Mbps - 33-40%
b) 22Mbps - 33-40%
c) 54Mbos - 30-47%
d) 54Mbps - 50-75%
e) 270Mbps - 50-75%
f) 270Mbps - 70-80%

Scroll down for answer.
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The answer is 'f'.

I was shocked for a moment. As that particular day, the only time I witnessed so many, > 100MBps connection in a single day.