The sum of the squares of the length of the chords intercepted on the circle, x² + y² = 16, by the lines x + y = n, n ∈ N where N is the set of all natural numbers is:

Correct option is D. 210
P = n², but n² < 4 ⇒ n = 1, 2, 3, 4, 5.
Length of chord AB = 2√(16 - n²/2) = 2√(32 - n²)/√2 ; n² = l (say)
For n = 1, l² = 62
n = 2, l² = 56
n = 3, l² = 46
n = 4, l² = 32
n = 5, l² = 14
∴ Required sum 62 + 56 + 46 + 32 + 14 = 210