8. In graphical method the restriction on number of constraint is A. 2 B.3 C. not more than 3 D. none of them. D. pivot element 10. Which of the following statements is true? A. A less than or equal to constraint with positive slack in the optimal solution will always have an infinite allowable decrease for the RHS. 9. Key element in the simplex method is also known as A. slack B. surplus C. artificial B. Increasing the RHS of a less than or equal to constraint will eventually make it redundant. C. Changing the RHS of a constraint changes its slope. D. Changing the RHS of a constraint changes its slope.