4. The number of subsets for a set consists of 4 element is? A. 6 B. 3 C. 12 D. 16 5. The pair for relation {(1,1),(2,1),(2,2),(2,3),(2,4),(3,1),(3,2)} on the set {1,2,3, 4} is A. reflective, symmetric and transitive B. irreflexive, symmetric and transitive C. not reflexive, not symmetric and transitive D. irreflexive, antisymmetric and transitive 6. The function f(x)=2x+13 from the set of integers to itself is onto. Is it True or False? A. True B. False 7. Which of the following function f:ZZ is not onto? A. f(x)=2x+3 B. f(x)=32+1 C. f(x)=53x D. f(x)=2x