Step 1: Recall from passage.
The passage clearly states that the botanical name of coconut is Cocos nucifera.
Step 2: Eliminate incorrect options.
- Papaya → Botanical name is Carica papaya.
- Arecanut → Botanical name is Areca catechu.
- Cashew nut → Botanical name is Anacardium occidentale.
Step 3: Conclusion.
Thus, Cocos nucifera refers to Coconut.
Final Answer: \[ \boxed{\text{Cocos nucifera = Coconut.}} \]
Fill in the blank with the correct option.
The teacher believed that the student’s sudden lack of interest in class was an ..........., as he had always been enthusiastic and attentive.