Consider the following statement. ∀a ∈ Z, (a − 1) a is not an integer. Select the correct negation for this statement.

a. For every integer a, a − 1/a is an integer.
b. For every integer a, a − 1 /a is not an integer.
c. There is an integer a such that a − 1/ a is an integer.
d. There is an integer a such that a − 1 /a is not an integer.