The maximum number of covalent bonds that nitrogen can form is 3. This is because nitrogen has 5 valence electrons, which means that it can share 3 pairs of electrons with other atoms. When nitrogen forms 3 covalent bonds, it achieves a stable octet configuration.
Option A is incorrect because nitrogen cannot form only 1 covalent bond. This is because nitrogen has 5 valence electrons, which means that it needs to share at least 2 pairs of electrons in order to achieve a stable octet configuration.
Option B is incorrect because nitrogen cannot form only 2 covalent bonds. This is because nitrogen has 5 valence electrons, which means that it needs to share at least 3 pairs of electrons in order to achieve a stable octet configuration.
Option C is correct because nitrogen can form 3 covalent bonds. This is because nitrogen has 5 valence electrons, which means that it can share 3 pairs of electrons with other atoms. When nitrogen forms 3 covalent bonds, it achieves a stable octet configuration.
Option D is incorrect because nitrogen cannot form 4 covalent bonds. This is because nitrogen has 5 valence electrons, which means that it can only share 3 pairs of electrons with other atoms.