The correct answer is option 1 - Sulphuric acid.

Sulphuric acid was the first mineral acid to be discovered. It was first prepared by the Persian physician and alchemist Ibn Sina (Avicenna) in the 8th century. Sulphuric acid is a strong acid and is commonly used in various industrial processes.

Option 2 - Hydrochloric acid, also known as muriatic acid, was not the first mineral acid to be discovered. It was first prepared by the German chemist Johann Rudolf Glauber in the 17th century.

Option 3 - Nitric acid was also not the first mineral acid to be discovered. It has been known since ancient times and was used by alchemists. It was first prepared in a pure form by the Arab alchemist Jabir ibn Hayyan.

Option 4 - Phosphoric acid is not the correct answer either. It was not the first mineral acid to be discovered and has been known since ancient times. It was first prepared in a pure form by the German chemist Heinrich Wilhelm Ferdinand Wöhler.

In conclusion, sulphuric acid was the first mineral acid to be discovered, making option 1 the correct answer.