This Application is made on the biography of rightly guided caliphs or khulafa-e-rashideen in english.
I hope all the single Muslim Brother and Sister Love this application.
The name of four khulafa....
1st Khulafa - Hadrat Abu Bakr Siddiq (RA)
2nd Khulafa - Hadrat Umar Farooq (RA)
3rd Khulafa - Hadrat Uthman Ghani (RA) &
4th Khulafa - Hadra Ali Bin Abi Talib (RA).