Statement: The alumni of the institute returned to rescue crumbling building of 112-year-old alma mater.
I. The Building of the institute was built 112 years ago at the time of its inception
II. The alumni visited the institute after a long period of time.
We can’t make out when was the building constructed. We also don’t know if the alumni had not visited the school in the interim, hence both assumptions are not implicit and option 4 is the correct answer.