If `I_(1)` is the first ionisation potiential `I_(2)` is the second ionsation potential `I_(3)` is the thirs ionsiation potential and `I_(4)` is the fourth ionisation potential of an element then which of the following has the laest value?
A. `I_(1)`
B. `I_(2)`
C. `I_(3)`
D. `I_(4)`