The correct option is B El Nino effect
Every few years unusually warm currents occur in the South Pacific Ocean of South America. This rise in temperature is due to a relaxation of the trade winds, that move the ocean waters throughout the globe. Without the trade winds, the surface waters rate of evaporation declines and heat loss slows. With the cooling of the South Pacific disrupted, unusually high temperatures occur along the coastal shores of Chile all the way up to Ecuador. El Nino is periodic increase in temperature, which fluctuates from a small increase in temperature.