The theoretical upper limit for the frequency of electromagnetic waves is:

Electromagnetic waves encompass a wide range of frequencies, spanning from low-frequency radio waves to high-frequency gamma rays. The energy carried by an electromagnetic wave is proportional to its frequency, such that higher frequency waves carry more energy.

The theory of electromagnetism posits that there is no maximum limit to the frequency of electromagnetic waves, implying that these waves could theoretically have infinitely high frequencies and consequently, infinitely high energies. Therefore, none of the answer choices A, B, or C, which suggest a limit to the frequency of electromagnetic waves, is correct. Likewise, answer choice E, which implies the presence of an upper limit, is also incorrect.