Landlord access to show unit to potential new tenant

[Garrett Pressick]

Hi All - This is my very first post to Bigger Pockets.  Here goes...

I have a small multifamily apartment building in Hagerstown, MD and in one unit I have a very uncooperative tenant.  Over the last year, she has caused all kinds of trouble.  Luckily, she is moving out at the end of her lease in February.  However, she is "refusing" to allow me to show the property to a potential tenant when she is not there and is threatening to notify the police if I attempt to show her unit.  Because of her temperament, I actually prefer that she not be there.  Below is what is stated in her lease:

SECTION 14: LANDLORD ACCESS

Landlord and Landlord’s agents shall have the right to enter upon the Premises at all reasonable times, with reasonable notice, for the purpose of inspection or making any repairs which Landlord may be required to make by reason of other provisions of this Lease or by reason of the requirements of public authorities. For a period of ninety (90) days prior to the expiration of the term of this Lease or any renewal thereof, Landlord shall have the right, at reasonable times, to show prospective tenants or purchasers the Premises and to post “For Sale” or “For Rent” signs thereon, if not prohibited by law, with reasonable notice to the Tenant. Except in an emergency, we shall give you at least one (1) day notice before we enter the Premises, and shall not enter the Premises unless you are present or you have consented to our entry, which consents shall not be unreasonably withheld.

My question is, do I actually have the right to show the apartment when she is not there?  Seems to me she is unreasonably withholding consent.  What do you all think?

Thanks in advance.