All of the alkali earth metals, group 2, have two valence electrons. which of these would represent the oxidation number of the alkali earth metals such as magnesium and calcium? a) -6 b) -2 c) +2 d) +6

Your answer should be C.) +2. "All the elements in Group 2 have two electrons in their valence shells, giving them an oxidation state of +2." 

Credits: https://chem.libretexts.org/Core/Inorganic_Chemistry/Descriptive_Chemistry/Elements_Organized_by_Blo...

Hopefully this has helped! :)

There is no reason to think the results are biased or not conducted properly but you should not assume the results are correct just because they were done in a laboratory so the answer would be c. it is likely to be reliable because the results support the conclusion presented.