Let's examine the choices we have:
A is wrong since halogens are non-metals
B is correct as halogens reacts with metals to form salts. Example of this is the reaction of sodium with chlorine to form sodium chloride
C is not completely right since I2 is liquid under ambient conditions and not gaseous.
D is wrong as they form negative ions of only -1 charges
E is wrong since they non-metals so they tend to form negative ions.
Based on this:
The right choice is: b. form salts with alkali metals with the formula mx
