Explanation:

- Option 1: for

- "For" is used to indicate a period of time.

- Example: "I have known her for 10 years."

- It is the correct choice for expressing the duration of the program.

- Option 2: Off

- "Off" generally indicates separation or removal.

- It doesn't fit the sentence context.

- Option 3: Since

- "Since" is used to indicate the starting point in time.

- Example: "I have been here since 2000."

- Not suitable because the sentence talks about duration, not a starting point.

- Option 4: Of

- "Of" usually shows association or belonging.

- It doesn’t work for indicating time duration.

Correct Answer: Option 1- for