DFT Efficient Computation on Digital Signal Processing related Questions and Answers

Question :   What is the sequence y(n) that results from the use of four point DFTs if the impulse response is h(n)={1,2,3} and the input sequence x(n)={1,2,2,1}? 1. {9,9,7,11} 2. {1,4,9,11,8,3} 3. {7,9,7,11} 4. {9,7,9,11} Answer :   4 - {9,7,9,11}