Which/Who is …, A, B or C? etc.
We add ‘the’ before the superlatives.
adjective
clean short cute happy
comparative
cleaner shorter cuter happier lazier bigger
Words, phrases and sentences you may use clever strong fast noisy exciting interesting dangerous delicious sweet healthy helpful smart generous humourous much+~er ~er than the ~est of the three/ of all/ in one's ... Which/ Who is ~er, A or B? Which/ Who is the ~est, A, B or C?
The first pig is quite fat.
The second pig is even fatter.
The third pig is the fattest among the three.
Compare them
Conclusion
1. We use comparatives to compare two people or things when we see … in the sentence than, much, even, still, a little, of the two , Which/Who is …, A or B? etc. 2. We use superlatives to compare three or more people or things when we see … the, of…, in …, among…