Step 1: Understanding the Concept:
This question is from Munshi Premchand's famous short story, 'January Night' (original title: 'Poos Ki Raat'). It focuses on the farmer Halku and his dog Jabra.
Step 2: Detailed Explanation:
Halku and Jabra are spending a freezing winter night in the field to guard the crops.
Jabra suddenly starts barking insistently. This barking alerts Halku that something is wrong.
Halku realizes that a herd of wild animals (specifically nilgai, or blue bulls) has entered the field and is eating his harvest.
Among the given choices, 'animals' is the correct general term for what entered the field.
Step 3: Final Answer:
When Jabra barked, Halku realised that wild animals had entered his field.