Answer:
e) halogens 
Step-by-step explanation:
Halogens - 
It is the group of elements present in the group 17 of the periodic table . 
Oxidizing agent - 
It is the process by which the process of oxidation takes place , 
It is the tendency of an element to oxidize other element by accepting electrons and reducing itself . 
In the electrochemical series ,  
Halogens are placed on the top of the series , and hence have the capability to act as a very good oxidizing agent , as they can easily accept electrons other elements and reduce themselves and thereby by oxidizing the other element .