Best friend VS Date

Hello all, I’m in a bit of a situation now and need some advice because I feel like my mind isn’t functioning properly on its own now. I’m 31 and I have a friend (35) who I proclaim as my best friend. We have known each other for nearly 7 years now and have regularly met and went out to trips (but never alone). We are close And comfortable with each other, even though we have very different personalities. 1 month ago, she confused that she had started developing her feelings for me several months ago. This came as a shock because she had mentioned that she will never date a friend. (And I had always had a closeted crush on her). Let’s call her A. Things escalated a little after a few drinks that night and we actually kissed for a while. And we kissed again and cuddled at her place two weeks later. Now at the same time, I’m dating this person B (30) who told me last year that she had a crush on me since 6 years ago when we first met. We were never much of a friend before that. After interacting with her, I realise she’s the kind of witty and fiercely protective person that I feel attracted to. However due to certain circumstances I have been hesitating to accept her. We had only held hands and had flirty gestures with each other but nothing more. I told B previously that I need time to sort out my life goals and values before I could commit. B said she will respect my final decision. A is aware of B’s presence since I had discussed about B with her before. She doesn’t want to be an alternative and said that she will leave if I can’t decide. B is aware that A is my best friend but is currently unaware of A’s feelings )and I don’t intend to tell her so). And now I’m torn between the two of them. I know that things won’t be the same between A and me, no matter what my decision is. I feel happier with B because she is so witty. But I’m also very trusting towards A as the quiet but always reliable soul. Both are also aware that I’m dating other people as part of my exploring journey. I often feel guilty that I’m hanging out with the two of them simultaneously. Is it possible to have feelings for both at the same time? How do you decide if your feelings are romantic or platonic?