Approach to property inquiry

[Christopher LeBlanc]

I'm wondering if there is a particular approach in the below scenario that is more appropriate.

The neighborhood my wife and I live in has two types of properties.  Half of the houses are single family, and the other half are duplexes.  We've lived in this neighborhood for about 15 years now, and it's a great place to live.  We've been increasingly interested in inquiring if we could purchase one of (and more in the future) the duplexes.  I was able to find out who owns them, and my question is this...

If you were to reach out to see if someone was willing to sell, would you

A. Make a cold phone call and just flat out ask if they were willing to sell (obviously be a little more in depth of a call)

B. Go *old fashioned* and type up a letter of sorts to send out, detailing our inquiry

My wife and I are split on it.  I think we should go with B, and my wife says just call them.  In my mind, it's more formal to go with B, but I'm interested to see what folks have to say about it.

For what it's worth, we own our house, as well as a condo we've been renting out for the past 10 years... however we've been looking to finally expand into some more properties (preferably two family+ which is why these are intriguing).  

Thanks for reading, and I appreciate any feedback provided, as well as any other ideas or options that we aren't thinking about currently.