When which digit in 467*15*23 is added 1

i will give one analogous example:

let volume of cuboid = 8*9*10 =720
which value(8/9/10) should be added 1 so the net result is least affected.

let add 1 to 8
vol= 9*9*10= 810 (change from original = 810-720 = 90)
let add 1 to 9
vol: 8*10*10 = 800 (change from original = 800-720 = 80)
let add 1 to 10
vol = 8*9*11 = 792 (change from original = 792-720 = 72)

so takeaway:
in order to have least effect always change the maximum value.

now in our example to have least effect on \(467*15*23\)
we need to keep 2 thing in mind
1)change the unit digit(Because if you change tens or hundred place then it will have larger effect thats common sense)
2)change the biggest number

so biggest number is 467 and unit digit of this 7.

hence D

hope this helps