Solution:The pattern followed here is :Each number is in the form of [(a³ - 1) : {(b³ - 1} : {(c³ - 1}], Where a, b and c are consecutive natural numbers
(26, 63, 124) → {(3)³ - 1}, {(4)³ - 1}, {(5)³ - 1} ⇒ (27 - 1), (64 - 1), (125 - 1) ⇒ (26, 63, 124)
Similarly,
(63, 124, 215) → {(4)³ - 1}, {(5)³ - 1}, {(6)³ - 1} ⇒ (64 - 1), (125 - 1), (216 - 1) ⇒ (63, 124, 215)
Hence, (63, 124, 215) is the correct answer.