a. Estimate the Product Backlog Items
b. The ordering of the Product Backlog Items
e. Brainstorming on the Product Backlog Items
Reasoning
Product Backlog Refinement is an activity where the entire team sits together and brainstorm around the backlog items. The backlog items are refined and the details are added to them.
During the meeting, the Product Backlog items are ordered based on their priority. Once the Product Backlog items have been refined, the Development Team members estimate the Product Backlog Items.