If the architecture describes the design by specifying gates
     If the architecture describes the design by specifying gates. Flip-flops, other hardware their interconnections it is called  behavioral description  structural description  combinational description  hardware description 
  
  Solution
Ans is 3
Because Combinational circuit is a circuit in which we combine the different gates in the circuit, for example encoder, decoder, multiplexer, demultiplexer, flip flop.
So it will be the Combinational description.

