Which is the best way to create new relationship?(a) letter, (b) phone call,(c) direct meet,(d)chatting, or (e) video conference?

Depends. If someone making a first contact I would be more happy to do it by email ( business partners etc. ), after that it is a good to make a call and arrange some meeting to "get to know each other a little better". After that, it is a crucial to keep a contact, but not to be too pushy, it  might cause contra effect. After some time it is polite to send "how are you" email or similar but again, do not be too pushy. Show that you care and keep your words ( in case of some agreement ) will show you as a great business partner and you relationship will be born.

Hi - A phone call is always required to fix up the meeting, some people are not always available on internet for chatting or video conferencing, some people even don't like too much of internet activities on cell phones, long distance relationship can be created through phone and if possible than meeting too, video conferencing is equally suitable where you can see the person online and talk.....

In my opinion,,The best way To create new relationship is a phone call because it preparing us to direct meet