Correct Answer: Inherent

Solution : The fourth option is the correct choice.

Innate means belonging to or determined by factors present in an individual from birth.  Inherent means existing as a natural and permanent quality of something or someone. It is clear that innate and inherent are similar in meaning.

The meanings of the other words are:

• Learnt refers to someone who possesses extensive knowledge or expertise in a particular subject or field.
• Inured describes someone who has become accustomed to unpleasant or difficult circumstances, often through repeated exposure.
• Inane signifies something lacking significance or intelligence, often trivial or foolish in nature.

Therefore, the correct answer is inherent .