Select the odd group of numbers. (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into its constituent digits. E.g.13 - Operations on 13 such as adding /subtracting /multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

(98 -78 -56)

Except option 3

Same logic is followed that  is subtraction 20  in previous number :

(92 -72 -52) = 92  , (92 - 20 = 72) , (72 - 20  = 52 )

(76 -56 -36) =  76  , (76 - 20 = 56) , (56 - 20  = 36 )

(98 -78 -56) =  98  , (98 - 20 = 78) , (78 - 22  = 56 ) which is odd

(88 -68 -48) =  88 , (88 - 20 = 68) , (68 - 20  = 48 )