Which of the following are examples of legal non-conforming uses?
A. A basement suite in an area near a university which has been zoned for single family dwellings for over 20 years. The suite has been in existence for 15 years and the municipality is aware of it.
B. A 25 year old corner grocery which is located in an area where the original zoning was changed from multi-family to single family two years ago.
C. A long-established factory in an area which has just been rezoned from industrial to residential.
D. A ski rental shop operating for 5 months of the year in an area which has just been rezoned to residential.

a. B and C are legal non-conforming uses.
b. A, B and C are legal non-conforming uses.
c. A and D are legal non-conforming uses.
d. C and D are legal non-conforming uses.