Explanation:

If it stopped spinning completely, every position on earth will have 1/2 year daylight and 1/2 year night time due to its revolution around the sun. If the rotation period slowed to 1 rotation every 365 days a condition called 'sun synchronous', every spot in the Earth would have permanent daytime or night time all year long. This is similar to the situation on the Moon where for 2 weeks the front-side is illuminated by the Sun, and for 2 weeks the back side is illuminated. Hence, statement 1 is not correct.

The magnetic field of the Earth is generated by a dynamo effect that involves its rotation. If the Earth stopped rotating, it's magnetic field would no longer be regenerated and it would decay away to some low, residual value due to the very small component which is 'fossilized' in its iron-rich rocks. There would be no more 'northern lights' and the Van Allen radiation belts would probably vanish, as would our protection from cosmic rays and other high-energy particles. Hence, statements 2 and 3 are correct.