In this task, you are given a sentence in the English language and your task is to convert it into the Hindi language. In translation, keep numbers as it is and make it sentence case (capitalize only the first word of each sentence and noun).

The cause of the rock fall is unknown, but police have said that there had been no prior signs that the cliff was unstable.
चट्टान गिरने का कारण अज्ञात है, लेकिन पुलिस ने कहा है कि इसका कोई पूर्व संकेत नहीं मिला था कि चट्टान अस्थिर थी।

They express concern about the possibilty that this could have been a terrorist aircraft with no transponder.
वे उस के बारे में चिंता व्यक्त करते हैं कि यह एक आतंकवादी विमान हो सकता है जिसमें कोई ट्रांसपोंडर नहीं है।

The Homeland Security group claims that the threat was for all of December.

होमलैंड सिक्योरिटी ग्रुप का दावा है कि यह खतरा पूरे दिसंबर के लिए था।