Choose the most suitable option to fill in the blank.

I was ______ on my toes when I sensed danger.

Correct option is D

Explanation:

The correct answer is immediately.

The phrase "on my toes" means to be alert or ready to respond quickly. The word "immediately" fits best as it means without delay or instantly, which is the required meaning in this context.

For example:
"She reacted immediately when she heard the alarm."
"The soldier was immediately ready when the enemy attacked."

Information Booster:

Meaning and Usage of "Immediately":
"Immediately" is an adverb that means instantly, at once, or without delay.
Example: "She left immediately after receiving the call."

Related Synonyms:

Instantly, promptly, right away, at once.

Additional Knowledge:

Quarterly (every three months, not suitable for urgency)
Example: "The company releases reports quarterly."

Annually (once a year, does not fit the context of urgency)
Example: "We celebrate New Year's Eve annually."

Tenderly (gently or with affection, not related to alertness)
Example: "She held the baby tenderly in her arms."