http://nces.ed.gov/surveys/piaac/figures/sample_num1.asp
First off, the statement describing the graph ("The following graph shows the number of births in the United States 1957 to 2007. Data is presented every 10 years.") is a bit odd. The graph shows the number of births per year for 6 of the 51 years from 1957 to 2007, at 10 year intervals. That's not really "the number of births in the United States 1957 to 2007." But let's say that's fine. Then they ask, "During which period(s) was there a decline in the number of births?" There is no such thing as "a decline in the number of births." The number of births always increases. There can be a decline in the rate of births per time, e.g., the number of births per year. But giving the number of births per year every ten years is not enough information to make a complete statement about births per time during the ten year periods. There may have been (and probably were) declines during each of those periods. In other words, it is impossible to "click all that apply."