Roberta was born in 1967, and so in 1976 she was nine years old. It is clear from this example that the last two digits of a person’s birth year will be the same as the last two digits of the year of that person’s ninth birthday, except that the position of the digits will be reversed.
Which of the following is the best criticism of the assertions made above

A．The generalization is valid only for those birth years that do not end in two zeroes.

B．The example does not exhibit the same principle as is expressed in the generalization based on it.

C．The generalization is valid only for those birth years in which the last digit is one greater than the second-to-last digit.

D．The example cannot be shown to be correct unless the truth of the generalization is already presupposed.

E．(E) The generalization is valid only for those birth years in which the last digit is greater than five.

债权人与债务人协议变更主合同的，应当取得保证人书面同意，未经保证人书面同意的，保证人不再承担保证责任。保证合同另有约定的，按照约定。（）