I saw this image on ->-bleeped-<- http://i.imgur.com/i8ML6.jpg
I really don't want to buy multiple outfit for different occasion.
Is there one outfit that can be used for all event

Phhht.

The point wasn't saying that women are expected and supposed to wear a variety of outfits to match a variety of occasions. It's sort of like a stereo type--"woman have huge wardrobes, and so they have the option of wearing a different outfit with a different feel for different events. Men, on the other hand, have compact wardrobes, limiting them to wearing one type of thing for many events."

Does this help?

I get the point. I'm minimalist. I would like to keep my wardrobe as minimum as possible. I need suggestion of what kind of outfit for women that is suitable for all of this event.

From my albeit limited understanding, every girl needs an LBD...  pretty much a safe fallback for just about any occassion...  Or so they say... find a style you like..

There is no one outfit that will carry you for all occasions..

Well, depending on how you carry it, a charcoal grey skirt/pants and blazer would probably cover everything except cocktails.  Women are expected to have diversified wardrobes, though. So don't be surprised if you get labeled as "That girl who always wears suits."