Internship Recommendation Letter

I completed my internship last summer, and will be returning to the firm full time. I’m planning on applying to some deferred MBA programs this year though and most of them require at least one rec letter from a professional “supervisor.” Is it appropriate to ask for one with the people I worked with over the summer? My team was also mostly analysts and I didn’t have a specific supervisor (had 1 manager and 4 project managers all of whom I worked with an equal amount). I was thinking about asking one of them, but I’m not sure that that’s something they usually do. Is a summer internship enough to go off of for a rec letter? Would it also look bad if I’m asking for a grad school rec? I wasn’t planning on leaving the company or the field as part of the considerations of pursuing and MBA