Correct Answer: Explicate

Solution : The correct choice is the fourth option.

Elucidate means to explain or make something clear. Explicate means to analyse and explain something in detail, similar to elucidate in its meaning of making something clear or explaining thoroughly.

The meanings of the other options are as follows:

• Exhaust means to use up completely or to drain someone physically or mentally.
• Examine means to inspect or investigate something closely.
• Oracular means relating to an oracle or having the characteristics of an oracle, which typically suggests being mysterious or prophetic.