Answer:
Option C
Explanation:
Total production of B from 2006 to 2011
= $ \left(750\times\frac{4}{5}\right)+\left(800\times\frac{7}{8}\right) $
+$\left(600\times\frac{4}{3}\right) +\left(550\times\frac{12}{11}\right)$
+$\left(700\times\frac{13}{14}\right)+\left(650\times\frac{14}{13}\right) $
= (600 + 700 + 800 + 600 + 650 + 700) tonnes = 4050 tonnes.
.'. Average production = $\frac{4050}{6}$ tonnes = 600 tonnes.