Step 1: Work out what "gender bias" means in numbers.
The question defines gender bias as the disproportion between the boys' drop-out rate and the girls' drop-out rate at a level. Since the table shows the girls' drop-out rate is higher than the boys' rate in every single year at every level, bias can simply be measured as (girls' rate minus boys' rate) for that level and year.
Step 2: Test the claim that primary bias steadily falls.
Primary bias in 1996-97 is \(40.9-39.7=1.2\). In 1997-98 it is \(41.5-37.5=4.0\), a rise, not a fall. Since bias needs to fall at every step for the claim to hold, and it rises in this very first step, the claim that primary gender bias has steadily gone down is false.
Step 3: Test the claim that bias falls from primary to secondary.
Take 1996-97 again: primary bias is \(1.2\), while secondary bias is \(73.7-67.3=6.4\). Bias is over five times bigger at the secondary level than at the primary level in this year, the opposite of what the claim says. So this claim is also false.
Step 4: Test the claim about the total primary drop-out rate falling steadily.
The total primary drop-out rate reads \(40.2\) in 1996-97, \(39.2\) in 1997-98, then \(41.5\) in 1998-99. The rate rises between 1997-98 and 1998-99, so it cannot be called a steady fall across the whole period. This claim fails too.
Step 5: Check the remaining claim, that secondary bias is always the biggest of the three levels.
In 1999-2000, elementary bias is \(58.0-52.0=6.0\) while secondary bias is only \(70.6-66.6=4.0\). Elementary bias beats secondary bias this year, so secondary bias is not always the largest either.
Final Answer:
Every specific claim about the table turns out to be false in at least one year, so none of them correctly describes the data.
\[ \boxed{\text{None of the above}} \]