Help! Interned and received a job offer. What if I take it and then reject it later on for something better?

I am currently in school getting my MBA while also interning at a company for the past 7 months. I will be graduating this spring and the company recently offered me a full-time position, however, I am still applying to other companies outside the area and have a few places that rank higher on my list than the place I am currently working for. But no other job offers yet. I also have a very good relationship with my boss and my boss's boss.

Ultimately I would like to find a job at one of the other companies ranked higher on my list, but I don't want to say no to this offer and risk not having a job when I graduate. I could accept the job now with the potential of declining it later and then risk ruining my relationships with my managers. Please let me know what you recommend doing.

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