FIA

Metamorphic rocks are formed when pre-existing rocks are subjected to great heat and pressure, causing physical and chemical changes without melting. This process alters the original rock into a new type, which is why option C is correct.

The word 'Inimitable' means something so good or unusual that it cannot be copied or imitated, which is synonymous with 'Matchless'. The other options do not convey this meaning.

The word 'obscene' means offensive or indecent, so its antonym is 'decent,' which means conforming to standards of propriety or morality. The other options either mean similar to 'obscene' or are not appropriate antonyms.

The word 'nugatory' means of no value or importance; trifling. Therefore, the synonym 'Trifling' correctly matches the meaning of 'nugatory'.

Hazrat Hamza RA is known as 'Sani as Nain,' meaning 'the second of the eyes,' because of his striking and beautiful eyes. This title is not associated with Hazrat Abubakar RA or Hazrat Nuh AS.

The word 'sprightly' means lively, energetic, or alert. Among the options, 'Alert' best matches this meaning, making it the correct synonym.

The Secretary General of the Organization of Islamic Cooperation (OIC) is appointed for a term of 3 years, which can be renewed. Therefore, option A is correct.

The correct modal verb to express obligation or necessity in this context is 'Must I do all his work tomorrow?' The phrase 'Need I do' is less common and sounds awkward here, while options C and D are grammatically incorrect.

William Henry Perkin is credited with inventing the first synthetic dye, mauveine, in 1856, which marked the beginning of the synthetic dye industry.

The jail system was introduced by Hazrat Umar RA during his caliphate as part of his administrative reforms to maintain law and order. This is a well-documented historical fact in Islamic history.