A group of Cummins Engine engineers come together after visiting multiple customer. They sit down and freely discussed new ideas to list ways the product might be redesigned without criticizing others ideas . This is an example of:

Brainstorming

Explanation:

Brainstorming is a form of group activity , in which members of the group will gather and combine their brain power to solve a certain problem or generate a unique idea.

In general, brainstorming tend to be more efficient in group problem solving. Even if the members point out an idea that is not necessarily good, other people could potentially pick up that idea and  adjust it into a better one.

During the brainstorming process, the members will be allowed to point out every small ideas that came up in their head. They do not have necessarily  to worry about the complex application of the idea. That part will come later with the help of other members.

i am pretty sure it is d.

they could find out our specific needs.