Fill in the blank in the sentence given below by choosing the correct option out of those that follow.
I promise to ________ you when I visit Delhi.

Correct option is A

The correct option to fill in the blank is (a) call up.
Detailed Explanation (English):
• The sentence expresses a promise to contact someone by phone.
• “Call up” specifically means to make a telephone call.
• Therefore, it is the most appropriate choice.
Correct sentence: I promise to call up you when I visit Delhi.
Grammatical Rule Used (English):
• “Call up” is a phrasal verb meaning to telephone someone.
• It can be used as: call up someone / call someone up.
Grammatical Rule Used (Hindi):
• “Call up” का अर्थ फोन करना होता है।
• इसका प्रयोग टेलीफोन द्वारा संपर्क करने के लिए किया जाता है।
Meanings of the other options:
• (b) Call at – to visit a place briefly (किसी स्थान पर जाना)
• (c) Call on – to visit a person, often formally or socially (किसी व्यक्ति से मिलने जाना)
• (d) Call for – to demand, require, or need something (मांग करना / आवश्यकता होना)