Consider the following statements: Statement I: In January, in the Northern Hemisphere, the isotherms bend equatorward while crossing the landmasses, and poleward while crossing the oceans. Statement II: In January, the air over the oceans is warmer than that over the landmasses in the Northern Hemisphere. Which one of the following is correct in respect of the above statements?

Statement I: Correct. In January, Northern Hemisphere landmasses are much colder than adjacent oceans, so isotherms dip equatorward over continents and bend poleward over oceans.
Statement II: Correct. Water cools more slowly than land, so in January the oceans are relatively warmer than nearby land in the Northern Hemisphere.
Link: Statement II explains Statement I because this land-ocean thermal contrast causes the isotherms to bend that way.
Therefore: (a) Both Statement I and Statement II are correct and Statement II explains Statement I.