let us review what we know.
1. every year since 1963, the agency's projected what the GNP would be 5 years later. i.e. projections were made for the years 1968, 1969, 1970, ... etc.
2. this projection was a serious underestimate.
3. Every year since 1963, they estimated the GNP of the previous year. So, estimates were made for 1962, 1963, 1964, ..., 1968, 1969, 1970,... etc.
4. this estimate is very accurate.
What does this imply? That in 1969, when they made an estimate for 1968's GNP they knew that the projection made in 1963 about 1968's GNP was a serious underestimate.
Which option states this? Option D.
Let us look at other answer options -
Option A - Incorrect.
We have no idea how Goro's GNP fluctuated between 1963 and 1994 because we have no data about the actual GNP values.
Option B - Incorrect.
"Prior to 1995, Goro had not released data intended to mislead the agency in making its five-year projections." -
Implies that Goro released data to mislead the agency after 1995. We cannot infer this.
Moreover, even if Goro did release data to mislead the agency, the argument and its points still stand.
Option C - Incorrect.
No such thing can be inferred from the paragraph. GNP could have been same over the years and thus amount of underestimation could have been the same.
Option E - Incorrect.
We cannot infer anything about its impact on economic planning.