Select the most appropriate option to fill in the blank.
The sergeant could not stand the weather because it was __________ cold.

Correct option is B

The correct option to fill in the blank is (b) bitterly.
• Bitterly (means very cold, unpleasantly cold.) (Hindi meaning: बहुत अधिक ठंडा, कड़ाके का ठंडा)
• As per the context, " bitterly cold" is a common English collocation describing extreme coldness.
Example:
· The wind blew bitterly across the open fields.
Explain why other options are incorrect:
· Smoothly – (Without difficulty or interruption.) (सहजता से)
· Cautiously – (In a way that is careful to avoid potential problems.) (सावधानीपूर्वक)
· Carefully – (Taking care to avoid mistakes or accidents.) (ध्यानपूर्वक)
Thus, "bitterly" is the only word that correctly and contextually fits the blank.