how to restrict navigation from one tabpage to another tabpage

hi,
in my tabcontrol i have four tabpages(a,b,c,d), iget request from customer he want to see a(tabpage),
my requirement is i dont want to navigate to another tabpages(b,c,d).
how to restrict navigation from one tabpage to another tabpage.... all tabpages are disable except selected tab...
plz any one help me....