The correct answer is Option B: (B) only.

In organic chemistry, ionic reactions typically involve heterolytic bond cleavage. This is when a bond between two atoms breaks and both electrons of the shared pair go to one of the atoms, creating ions. One atom becomes a positively charged ion (cation), as it loses an electron, and the other becomes a negatively charged ion (anion), as it gains an electron.

In contrast, homolytic bond cleavage occurs when each atom gets one electron from the shared pair, leading to the formation of two free radicals, which are highly reactive species with unpaired electrons. However, this is not typically how ionic reactions proceed in organic compounds.

The options (C), (D), and (E) mention free radicals. Since homolytic cleavage leads to free radicals, and we've established that ionic reactions in organic chemistry generally proceed through heterolytic cleavage, free radicals are not typically involved in these reactions. Therefore, these options are not correct in the context of ionic reactions with organic compounds.

Thus, the process of heterolytic bond cleavage (B) is the mechanism through which ionic reactions usually occur in organic chemistry.