Select the sentence with the appropriate use of prepositions. 

The correct answer is: It has been raining since morning. 

Key Points 

• Let us look at the meaning of the given prepositions.
  • Till: Up to the point in time or the event mentioned. (समय तक या उल्लिखित घटना तक)
  • From: Indicates the point in time at which a particular process, event, or activity starts. (उस समय को इंगित करना जिस पर एक विशेष प्रक्रिया, घटना या गतिविधि शुरू होती है)
  • By: Identifies the agent performing an action. (कार्रवाई करने वाले एजेंट की पहचान करना)
  • Since: From a particular time in the past until a later time, or until now. (अतीत में किसी विशेष समय से बाद के समय तक, या अब तक)
    • For example- I haven't eaten since breakfast.
• The given sentence is saying that the rain has started in the morning and it is still continuing.
• We use since as a preposition, a conjunction and an adverb to refer to a time, and as a conjunction to introduce a reason.
• So, as per the meaning of the given prepositions "since" should be used here.

​Therefore, the correct answer is option 4.