You are trying to install BeautifulSoup 3, which is not Python 3 compatible. As the Pycharm error window explains:
Make sure you use a version of Python supported by this package. Currently you are using Python 3.5.
However, you want to install BeautifulSoup 4 instead; the project name for that series has changed to beautifulsoup4. BeautifulSoup 4 has been out for a few years now and supports Python 3.