All numbers divisible by 100 are divisible by 25.
all numbers divisible by 25 are divisible by 5.
conjecture: all numbers divisible by 100 are divisible by 5.

use deductive reasoning to verify the conjecture, or provide a counterexample if the conjecture is false.

a.
true; law of detachment
b.
true; law of syllogism
c.
false; 75 is divisible by 5, but 75 is not divisible by 100
d.
false; 200 is not divisible by 5