Which statement describes the negative effects of El Niño?a.El Niño appears every 2 to 12 years.b.Rain, flash floods, and mudslides occur in places where there is usually little rain, while usually wet areas suffer from drought.c.Sometimes El Niño is followed by La Niña, during which ocean temperatures become cooler.d.Upwelling along the coast of South America occurs after an El Niño.