Answer:
The correct answer is : proton and electron (opposite charges).
Step-by-step explanation:
Water is a polar molecule as it has equal number of electron and proton. Electron and protons are present on different end of water molecule, negative charge due to electrons at end of oxygen, while positive charge at end of hydrogen due to protons.
Equal number of electron and proton make it neutral or no net charge molecule however having opposite charge on its end makes is polar.
Thus, the correct answer is: proton and electron.