Change to another option, showing intelligence in school (6)
I believe the answer is:
switch
'change to another option' is the definition.
'intelligence in school' is the wordplay.
'intelligence' becomes 'wit' (wit is a kind of intelligence).
'in' is an insertion indicator.
'school' becomes 'sch'.
'wit' inserted inside 'sch' is 'SWITCH'.
'showing' is the link.
(Other definitions for switch that I've seen before include "Circuit breaker; change" , "One may be off" , "Contact maker or breaker" , "birch" , "Device for opening or closing a circuit" .)