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The answer depends on the use of these words (actually marks as NYPD is a trademark that belongs to NYC)
Under the diminutive use doctrine one can mention a trademark without permission provided confusion is not created in consumers as to the use of the mark. For example, it should be ok to mention that "the NYPD recommends never to talk to strangers" (if in fact they recommend this).
what do you intend the ad to be?
I was asked to switch to Q&A mode since you indicated you could not see my request for information.
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