Thanks a lot. I had already thought of the kind of price definition. This also makes the most sense.
I came up with the question because I had seen some coins (marketcap ranking 200+) that were listed on a few exchanges and which had a huge price difference and yet Coinmarketcap has a completely different price displayed, which did not open to me.
I always thought it was something like a volume-weighted average, so a mix of both your guesses.
[EDIT] Here:
How are the prices calculated for various the cryptocurrencies?
Price is calculated by taking the volume weighted average of all prices reported at each market. Sources for the prices can be found on the markets section on each cryptocurrency page. For example, Bitcoin's markets.
Source:
http://coinmarketcap.com/faq/