Which element is a metalloid? B. Silicon (Si)
Looking at the periodic table, which element is a metal? D. Strontium (Sr)
Argon (Ar) is a noble gas, silicon (Si) is a metalloid, hydrogen (H) is a non-metal, and strontium is a alkaline earth metal.
I have used the periodic table from http://chemreference.com/elements/1/properties?display=periodic&trend=number to help me when I'm unsure.