(b) If underground storage tanks are located at adjacent parcels of real property, the adjacent parcels together constitute one site if both of the following apply:

1. (1) The underground storage tanks are, or have been, operated by the same person.
2. (2) The adjacent parcels are under common ownership or control.

(c) Notwithstanding subdivision (a), the board may consider a parcel of real property as consisting of multiple sites, corresponding to the number of distinct underground storage tank operations at the parcel, if the board makes both of the following findings:

1. (1) There is more than one underground storage tank located at the parcel.
2. (2) Each separately operated underground storage tank or group of underground storage tanks is not, and has not been, operated by a person who is operating or has operated another underground storage tank at the same parcel.