(b) That's correct. Generally, anything a tenant brings onto the leased premises remains their own property, and they have the right to remove those things at the end of the lease. But if the tenant actually affixes something to the land or buildings that thing can become a 'fixture' and may therefore become part of the land itself. Whether or not something has become a fixture and part of the land is a question of fact, depending on all the circumstances of the case. There are two main factors which will be taken into account.
First, the degree of annexation is considered. If something is attached to the land or buildings rather than resting by its own weight, then it is presumed to become part of the premises. Something resting by its own weight, such as a pile of blocks, generally remains the tenant's property.
Second, the purpose of annexation (the tenant's intention) is considered. If the thing was intended to be attached permanently, as an enhancement to the premises, then it becomes part of the land. But if it was attached only for a temporary purpose, or so it can be better used or enjoyed, it is probably not a fixture. For instance, machinery that has been attached to the floor only to stabilise it would probably remain a chattel rather than a fixture. A tenant usually has the right to remove their fixtures at the end of a lease. Exceptions are when removal would cause substantial damage to the property, or when the lease indicates that fixtures must not be removed.