Q1:

What is this circuit?

ANS:D - a band-stop filter

The given answer is correct because of a parallel combination of low pass filter and high pass filter. So the entire spectrum is given to both the filters. If there is an overlapping (upper cut off frequcy of lpf is greater than lower cutoff frequency of hpf) then it acts as a band stop filter.

It's not a bandpass filter because in a bandpass filter the low pass filter is followed by high pass filter (i.e, if they are cascaded or series combination) Before identifying a filter characteristics once check whether they are cascaded or in sires along with there characteristics and order.