Conflict at work and friendship

Okay, there is a Mrs A and Mrs B, both are older than myself; I should say 20 years older. A and B were friends but had some misunderstanding so stopped being close so B became my older friend who I talk to for advice. Some month ago A started bring snacks, nuts and cookies to B and B was happy to receive these gift, however B works at a separate building and I had to receive the gifts from A everyday I went to work and I had to walk all the way to where B was and give it her, so last week I told A, I am tired of walking all the way there to give these snacks to her which A replied “ I will text her to pick it up” knowing fully that B won’t and she A being afraid of B won’t be able to say a word about B picking up her snacks.
Yesterday I was at work when A said to B “I thought you guys were cool, I told her to bring the snacks to you but she said she was tired of bringing it”
So B spoke to me after A left “if you don’t want to take it from her and bring it to me, I understand but I prefer that you never told her that you don’t want to do it. If bringing the snacks to me as a friend is too hard for you, I wonder if I have a bigger problem in the future you will be willing to help me”
So here is my question
Why would A tell B, what is she trying to get from this?
What does B mean by, I shouldn’t have told her that I didn’t want to
I am confuse on what to do
When I came to work today, A was all smiling like something great happened to her, she made a comment to one of my coworkers “ I get fuzzy when I want something but can’t have it.
I haven’t called B since the incident and keep feeling like she was just treating me like a slave always wanting me to walk to her building with her snacks, but B has been a great help since I knew her. I don’t know what to do