The answer is the second option. The given conversion from L to dm3 is actually confusing. Just remember that 1 L = 1000 cm3.
Simply, multiply 2.6 by 1000 and we get 2600 cm. Converting this to scientific notation, we get the answer:
2.6 x 10^3 cm3
I think it is C, because a covalent bond is a distribution of 2 atoms to 1 electron, meaning they are sharing and not exchanging, and the electronegravity would be above 1.7
A, because all elements in a same group/family will always have similar properties with each others.