Answer: the best option to answer the question is letter A
Step-by-step explanation:
The question requires us to choose the option that presents the formula of two alkanes.
Alkanes are hydrocarbons that are saturated and acyclic (i.e., the molecule of an alkane do not present double or triple bonds between carbons and it is a linear structure). The general formula of alkanes tells us that there are double plus 2 the amount of hydrogen atoms as there is carbon atoms, as it follows:
where n indicates the number of carbon atoms in the molecule.
For example: we can say that the compound C2H6 is an alkane because it contains 2 carbon atoms (n = 2) and 6 hydrogen atoms (2n +2= 6).
Considering the options given by the question, only option A presents the formula of two alkanes:
CH4: n = 1; 2n+2 = 2+2 = 4
C8H18: n = 8; 2n+2 = 16+2 = 18
Therefore, the best option to answer the question is letter A.