Answer:
Rb
Explanation:
This is because they are in the same group which means they share similar properties.
 
        
             
        
        
        
The correct answer is 1) Ag, Si, I₂
Ag or silver is a metal. Silver is a transition element which lies in the d-block of the periodic table. 
Si or silicon is a metalloid. Silicon is a metalloid which lies in the p-block of the periodic table. 
I₂ or iodine is a nonmetal. Iodine is a halogen which lies in group 17 of the periodic table. All halogens are nonmetals.