The correct answer is equatorial pacific ocean.
Equatorial pacific ocean is a body of water is home to the ENSO cycle.
ENSO cycle refers to southern Oscillation or El Nino. The interaction which occurs between ocean and atmosphere in tropical pacific results to periodic differences.
The three phases of ENSO include La nina, El Nino and neutral phase. ENSO lasts for nine to twelve months. They mostly develop on March to June and weaken on May to July.
ENSO is caused when atmospheric pressure across the pacific of equatorial.