You plan ahead (so that you know your responses) and respond directly. My primary interests are x and y, but I also would be greatly interested in z. Of course, if there is at least some overlap, then you're likely to be looked at a bit more favorably than a scatterbrain who used a magic 8-ball to create your application list.
Additionally, as JuniperTree mentioned, you should be tailoring your apps for each program anyway. So you're not "lying" or "deceiving" anyone if you tell them that your interests are 'x' and 'y', which are compatible with their program (but you perhaps leave out that you have other interests that are not quite so compatible with their program).
During my second round of applications, I applied to more programs than could even be listed on the limited space where they ask to "what other programs are you applying? I tended to list those programs that were comparable to the one for that application, and that had research faculty with similar interests as that particular program.
Geographical convenience is a bit trickier, but I would still stand by the above. Tailor your app to the program. Find *something* (other than location) that the program has going for it as to why you want to attend there. Research, clinical opportunities, or whatever the case may be.
I had a prof during an interview who suggested that the program's location might not be ideal for me due to the significant differences in weather compared to where I was living previously. (Oddly, this was brought up repeatedly...
) Again, be prepared to discuss their location if necessary, i.e., either why it's an ideal fit for you or (if not) how you intend to overcome those challenges (and how you're more interested in the program, not the location anyway).
Buuuut, a lot of this occurred much later, during the interview stages... Something to be thinking about though when crafting those SOPs.
G'luck, folks!