Which one among the following is the primary reason of microwave heating of water?

Microwave heating is based on the principle of dielectric heating. Water molecules are electric dipoles, meaning they have a partial positive charge at the hydrogen end and a partial negative charge at the oxygen end. When subjected to the rapidly oscillating electric field of microwaves (typically 2.45 GHz), these dipoles attempt to align themselves with the field. This rapid rotation (dipole rotation) causes molecular friction and collisions, which convert electromagnetic energy into thermal energy (heat). This interaction at specific frequencies is often described as rotational resonance in a broad sense. Microwaves are non-ionizing radiation, so they cannot ionize molecules (ruling out A). Standing waves (C) explain the distribution of heat (hot spots) but not the mechanism of heating. Induced currents (D) are the primary heating mechanism for conductors (metals), not dielectrics like water.