YES

(VAR )
(RULES
  response(a(),b()) -> b()
)

(COMMENT
Termination is shown by EKBO with interpretations on natural numbers

  response_A(x1,x2) = 1
  a_A = 1
  b_A = 1
  response#_A(x1,x2) = x1 + x2
  a#_A = 0
  b#_A = 0

weights

  w0 = 1
  w(response) = 0
  w(a) = 1
  w(b) = 1

and precedence:

a > response > b
)