95% of the incomes of members of the population are between X - $10,000 and X + $10,000.

95% of the incomes of members of the population are between $19,000 and $21,000.

In 95% of all possible samples X is between $19,000 and $21,000.

In 95% of all possible samples the sample average will be between X - $1000 and X + $1000.

How many of the above statements are certainly true?

a. one b. two c. three d. four e. none