Leticia radio is getting interference whenever she uses it in her dining room. What's the most likely reason/s.

D. There is a dimmer switch

Explanation:

Dimmer switches have been known to cause radio interference especially the solid state ones. To counter this, dimmer switches usually come with a component to suppress radio interference, this doesn't work for all dimmers and the cheaper dimmers are usually more prone to this problem.

If Leticia's dining room makes use of a dimmer switch, it is the most probable reason for radio interference.  

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a true.