"The mean of `1^2,\ 2^2,\ 3^2,\ 4^2,\ 5^2,\ 6^2,\ 7^2`is(a) 10 (b) 20 (c) 30 (d) 40"

"The mean of `1^2,\ 2^2,\ 3^2,\ 4^2,\ 5^2,\ 6^2,\ 7^2`is(a) 10 (b) 20 (c) 30 (d) 40"

"The mean of `1^2,\ 2^2,\ 3^2,\ 4^2,\ 5^2,\ 6^2,\ 7^2` is (a) 10 (b) 20 (c) 30 (d) 40"