Q1: What kind of logic device or circuit is used to store information?

ANS:B - Register

Simply we can say that buffer is to hold the data (i.e it doesn't store the data) but register made of flip flop can store data.

We can say the content present in buffer is not stored and so it will get automatically deleted because it makes delay in the propagation of data which seems to be saved, but it is not actually stored in buffer.