Find out the FALSE statement:

Option A: The growth rate of covered wagons in 1996 over 1995 = $$\frac{\left(114065-121946\right)}{121946}\times\ 100=-6.5\%$$

The growth rate of covered wagons in 2000 over 1999 = $$\frac{\left(86024-96371\right)}{96371}\times\ 100=-10.5\%$$

Since this is true, option A is not the correct answer.

Option B: 

The annual growth rate of open high sided wagons in 1997 over 1996 = $$\frac{\left(98906-98297\right)}{98297}\times\ 100= 0.62\%$$

The annual growth rate of open high sided wagons in 2003 over 2002 = $$\frac{\left(90765-90371\right)}{90371}\times\ 100= 0.44\%$$

Since this option is also true, option B is not the correct answer.

Option C:

The annual percentage growth rate of average wagon capacity in 1999 over 1998 = $$\frac{\left(42.3-40.5\right)}{40.5}\times\ 100= 4.4\%$$

The annual percentage growth rate of average wagon capacity in 2001 over 2000 = $$\frac{\left(45.9-43.8\right)}{43.8}\times\ 100= 4.8\%$$

Since this option is false, this is the correct option.

Thus, the correct answer is C.