Concept:The arithmetic mean is the total sum of all values divided by the number of values.Explanation:The given values are 2−t, 4+t, 3−2t, 2+t, and t−1.There are 5 values, so the denominator is 5.Find the sum of the constant numbers:2+4+3+2−1=10.Now find the sum of the t-coefficients:−t+t−2t+t+t=0.So the total sum becomes:(2−t)+(4+t)+(3−2t)+(2+t)+(t−1)=10+0=10.Mean =number of termssum=510=2.Answer:The mean is 2, which is Option C.