Correct option is C
The correct answer is: (c) It means the independent or original interpretation of problems not precisely covered by the Quran.
Detailed Explanation
In Islamic jurisprudence (Usul al-Fiqh), Ijtihad (literally meaning "striving" or "exerting total effort") refers to the process of making an independent legal reasoning or original interpretation to derive a legal ruling (hukm) on a novel issue or problem not explicitly covered by the primary sources (the Quran and Sunnah).
A qualified scholar who exercises Ijtihad is called a Mujtahid.