The shopkeeper asked Ramesh which book he wanted. Ramesh replied that he wanted a reference book for Physics which he could use for his project work.
In reported speech, the question “What book do you want?” changes to “which book he wanted,” with the verb tense shifting from present to past.
Ramesh’s response is also reported by changing “can use” to “could use,” maintaining the original meaning while adjusting for tense.
This ensures the dialogue is clearly and correctly conveyed in indirect speech.