Answer (A, C) ∴ f (2 – x) = f (2 + x) ...(i) Replace x by (2 – x) : f (x) = f(4 – x) ...(ii) given that f(20 – x) = f(x) ...(iii) for (ii) and (iii) : f (4 – x) = f(20 – x) ...(iv) Replace x by 4 – x : f (x) = f (x + 16) ...(v) In eq. (iii) Replace x by (10 – x) : f (10 + x) = f (10 – x). ∴ f(x) is symmetrical about line x = 10.