The total export of foodgrain A in 2017 and 2018 is what percentage Less than the total domestic consumption of foodgrain B in 2017 and 2019?

A's export in 2017 = $$300\times\ \frac{40}{100}=120$$
A's export in 2018 = $$400\times\ \frac{45}{100}=180$$
A's total export in 2017 + 2018 = 300

B's domestic production in 2017 = $$350\times\ \frac{66}{100}=231$$
B's domestic production in 2019 = $$300\times\ \frac{73}{100}=219$$
B's total domestic produce in 2017 + 2019 = 450

A's export is 150 million tonnes less than the B's domestic produce. 
The percentage required  = $$\frac{150}{450}\times\ 100=33.33\%$$

Therefore, option C is the correct answer.