a) is Reflexive( because everyone who has visited web page a has also visited web page a), Not Symmetric( because if everyone who has visited web page a has visited web page b, this does not mean that everyone who has visited web page b has also visited web page a), Not antisymmetric(because if everyone who has visited web page a has visited web page b and everyone has visited web page b has visited web page a, it does not necessarily mean that a and b are the same web page), Transitive( because if everyone who has visited web page a also has visited web page b and everyone who has visited web page b also has visited web page c, then it follows that everyone who has visited web page aa has also visited web page c)
b) Relation R would be something like R(a,b) = Linkoutof(a) intersection Linkoutof(b) = NULL
Not Reflexive, Symmetric, Not AntiSymmetric: (two distinct pages may have no common links), NOT Transitive.
c) Relation R would be something like R(a,b) = Linkoutof(a) intersection Linkoutof(b) != NULL
Not Reflexive: (some pages have no outgoing links), Symmetric, Not AntiSymmetric: (two distinct pages may be have a common links), Transitive.
d) is Not reflexive(because a cannot be taller than itself), Not symmetric(X is taller than me. I am not taller than X), Transitive, AntiSymmetric(clearly)
e) is reflexive, symmetric, transitive, not antisymmetric (Two distinct people may be born on the same day)
f) is reflexive, symmetric, transitive, not antisymmetric (Two distinct people may have same first name)