Answer:
B. Law of syllogism.
Explanation:
The deductive reasoning behind the set of arguments is the Law of Syllogism, defined by the following logical rule:
1) 
2) 
Hence,
3) 
In this case, we have three simple propositions:
A number ends in 0.
A number is divisible by 10.
A number is divisible by 5.
The reasoning represented by the consecutive arguments is:
1) If a number ends in 0, then it is divisible by 10.
2) If a number is divisible by 10, then it is divisible by 5.
Hence,
3) If a number ends in 0, then it is divisible by 5.