How to inform a prospective tenant they did NOT get approved

[Tony Castronovo]

After screening prospective tenants and making a selection, am I obligated to let the applicants who did NOT get approved know why they didn't make it?  Not sure if it's best to "say nothing"....be vague....or tell them specific reasons.  I had two applicants that invested a lot of time in the process and had to choose one.  Have not yet let the applicant who didn't get the property know but need to today.