I believe the correct answer from the choices listed above is the first option. The compound that contains both ionic and covalent bonding is KOH or potassium hydroxide. It contains one covalent<span> (O-H) and one that is </span>ionic<span> (K-O). Hope this helps.</span>
Answer and Explanation:
The Fremy salt is a chemical compound its chemical name is disodium nitrosodisuphonate
The molecular formula of the Fremy salt is 
When phenol is treated with Fremy salt in presence of water then benzoquinone is formed
( in presence of Fremy salt and water)
Ca₁₀(PO₄)₆(OH)₂ - hydroxyapatite
b. phosphorus (P) and calcium (Ca)