Final answer:
The expression 2ab - 4a + 5b + 6ab has 3 constants: -4a, 5b, and the coefficient 2 of the term ab.
Step-by-step explanation:
The expression 2ab - 4a + 5b + 6ab has 3 constants.
Constants are terms that do not have any variables attached to them. I
n this expression, the constants are -4a, 5b, and the coefficient 2 of the term ab.
Therefore, the answer is B. 3.