Answer:
(B)The expression (5n)(9-p) is the product
(D)The expression 9-p has exactly two terms
Explanation:
In the expression;

The coefficient of m is 1, therefore Option A is not true
The product of 5n and 9-p is (5n)(9-p), therefore Option B is true.
The expression 9-p has exactly two terms,9 and p.
Therefore, Options B and D are true.