The correct option is B Trinomial
The given expression is,
(6xy−8x+9y+4)−(5x+2yx+9y+4−xz).
Simplifying the expression, we get
=(6xy−8x+9y+4)−2xy+xz−5x−9y−4)
Grouping all the like terms, we get,
= [(6xy−2xy)+xz+(−8x−5x)+(9y−9y)+(4−4)]
= (4xy+xz−13x)
An algebraic expression which has three non zero unlike terms is called a trinomial.
Thus, the given expression is a trinomial.