for the purposes of section 5(1)(a), means a lease which—
| a) | was entered into for a period of not less than 10 years; |
| b) | was entered into for the natural life of the lessee or of any other person mentioned in the lease; or |
| c) | is renewable at the will of the lessee indefinitely or for periods which, together with the first period, amount in all to not less than 10 years; |