Concept:The mean is the total sum of all data values divided by the number of values.Explanation:The given numbers are 13,16,x,18,21,2x,35.There are 7 numbers in total, and their mean is 22.Sum of the numbers:13+16+x+18+21+2x+35=103+3xUsing the mean formula:7103+3x=22Multiply both sides by 7:103+3x=154Subtract 103 from both sides:3x=51Divide both sides by 3:x=17Answer:x=17, which is Option B.