I am designing a study where I'd like to allow respondents to pick a base cause that they most support and then select what, if any, actions they would participate in. For example, let's say we want to look at a bunch of charitable organizations. I'd want them to pick one charity that they most support (Susan G Komen, ALS, JDRF, American Cancer Society, etc.) and then some of the initiative they might participate in, (marathons, walk-a-thons, general fundraising, etc.) there would likely be multiple options for multiple categories, but they would be "add-ons" so that's what makes me think MBC is the appropriate CB model. But without an element of price is this doable? Is there something that would be more appropriate?