Answer:

D.

Explanation:

The given question is related to the concept of 'Indian Ocean Dipole (IOD)'. Let's discuss each option one by one:

a) Indian Ocean Dipole is a phenomenon related to the movement of water currents in the Indian Ocean. This statement is incorrect as IOD is not related to the movement of water currents. It is related to the difference in sea surface temperature between two areas in the Indian Ocean.

b) Indian Ocean Dipole is a phenomenon related to the monsoon winds in the Indian Ocean. This statement is incorrect as IOD is not related to the monsoon winds. It is related to the sea surface temperature difference between two areas in the Indian Ocean.

c) Indian Ocean Dipole is a phenomenon related to the El Niño effect in the Indian Ocean. This statement is incorrect as IOD is not related to the El Niño effect. It is a separate phenomenon that occurs in the Indian Ocean.

d) Indian Ocean Dipole is a phenomenon related to the sea surface temperature difference between two areas in the Indian Ocean. This statement is correct as IOD is a phenomenon related to the difference in sea surface temperature between two areas in the Indian Ocean. The IOD is characterized by a positive phase, where the western Indian Ocean is warmer than the eastern Indian Ocean, and a negative phase, where the eastern Indian Ocean is warmer than the western Indian Ocean.

In conclusion, option D is the correct answer as it correctly explains the phenomenon of Indian Ocean Dipole.