Identify the part of the following sentence that has an error in it.
Hardly had (A) he left home (B) than it (C) began to rain. (D)

Correct option is C

Option (c) contains an error.
Detailed Explanation (English):
• The structure “Hardly/Scarcely/Barely + had + subject + V³” is an inversion pattern used to show that one event happened immediately after another.
• With “hardly/scarcely/barely”, we use “when”, not “than”.
• “Than” is used with “No sooner … than”.
• Therefore, “than it” is incorrect; it should be “when it”.
Correct sentence:
Hardly had he left home when it began to rain.
Grammatical Rule Used (English):
• Hardly/Scarcely/Barely + had + subject + V³ + when + Simple Past
• No sooner + had + subject + V³ + than + Simple Past
Grammatical Rule Used (Hindi):
• “Hardly/Scarcely/Barely” वाले inversion structure में “when” आता है, “than” नहीं।
• “No sooner” के साथ “than” आता है।
• इसलिए “Hardly had … than” गलत है; सही होगा “Hardly had … when”.
Example:
Hardly had I reached the station when the train arrived.