A virtual whiteboard is a technique that a business analyst can use to optimize effectiveness and build a shared understanding of an idea and approach with sales users in various locations. A virtual whiteboard is an online tool that allows multiple participants to collaborate visually by drawing, writing, or annotating on a shared screen. It can help them brainstorm ideas, create diagrams, or give feedback in real time. A demo prototype is a technique that can be used to show how an idea works or looks like, but not to collaborate on it. One-on-one meetings are techniques that can be used to communicate with individual stakeholders, but not with a group.
References:
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/collaboratio
https://trailhead.salesforce.com/content/learn/modules/salesforce-business-analyst-certification-prep/user-stories