Name the first Sahabi who murdered disbeliever in the way of Allah?

Posted by

(a) Hazrat Saad bin Abi Waqqas (RA)
(b) Hazrat Umar (RA)
(c) Hazrat Hamza (RA)
(d) Hazrat Ali (RA)

See also  What is the fifth belief in Iman-e-Mufassal?