Yes, it is clearly considered as harassments in the workplace.

It sounds as you are in conflicting situation. If you are not able to resolve this situation yourself, the second best you can do is to discuss with your superior how to resolve this conflict. The job of your superior is to properly address the conflict and to reach a resolution which will benefit the most.

Note, not every situation will be resolve in your favor.

Not harrassment, but a complete shutdown of communication can still land you in hot water.

You are never obligated to be friends with people, but in a work setting, you may be obligated to open communications enough to have purely work-centric conversations, barring any situation that could make the company legally liable (eg: sexual harassment), which doesn't seem to be the case here.

If your lack of talking becomes a work production barrier, you will soon start to see company action being taken against you in order to remove such barriers, which is why a total communication shutdown is not a good idea.

So long as you keep purely work-related conversations productive, you can shut down any attempts at small talk or social conversation. How you do this is up to you, but I believe honesty is a good policy here.

I had a similar problem. I took my coworker to the side and told him that his behavior is NOT acceptable. I told him that I don't like him, and I will never like him. I said had 0 things in common but at work we have to be loyal to each other and use politics that fit us both so we can co-exist in the same company. His face changed like he got choked up and almost started crying, and he was sad but after that he knew not to mess around with me and with time we actually became friends. We are good friends today, and we hang out after work too.

Basically your co-worker feels threatened by you since you probably are more liked than he is and solve problems faster.

Coworker B is not friendly to me after, so I decide it is best to not talk to her.

That's fine, workplace is not primarily meant for making friends. If she's not talking to you, you also don't need to force yourself.

However, keep in mind, do not let this situation override professionalism. If Coworker B needs to talk / discuss with you at any point about any work related item, you need to comply. Again you don't need to engage them beyond the scope of work, have the discussion, conclude it and go on your way. If you feel they are trying to strike a side-conversation for whatever reason, politely ask to be excused and get back to your work. Same is applicable from your side also, if you need their help, approach them like you'd do for any other co-worker, setup a formal meeting if it's more than a 5 minute talk, and focus on getting the work done.