17, 19, 20, 17, 23, 15,....., .....A21,10B22,13C26,12D26,13Answer: D. 26,13 Read Explanation: 1.series 17,20,23,26 17+3=20 20+3=23 23+3=26 2.series 19,17,15,13 19-2=17 17–2=15 15–2=13Read more in App