Solution:The pattern followed here is :{(1st number × 2) - 1} = 2nd number & {(2nd number × 2) - 2} = 3rd number
(19, 37, 72) → {(19 × 2) - 1} = 37 & {(37 × 2) - 2} = 72
(15, 29, 56) → {(15 × 2) - 1} = 29 & {(29 × 2) - 2} = 56
Similarly,
(11, 21, 40) → {(11 × 2) - 1} = 21 & {(21 × 2) - 2} = 40
Hence, "(11, 21, 40)" is the correct answer.