Which of the following has fractions in descending order ?

In order to find the order of the fractions in descending order, we should represent all the fractions with the same denominator.
In order to do this, we should find the LCM of 8,7,3 and 5.

The LCM of 3,5,7 and 8 is 840.
$$\frac{2}{3} = \frac{560}{840}$$
$$\frac{3}{5} = \frac{504}{840}$$
$$\frac{5}{7} = \frac{600}{840}$$
$$\frac{7}{8} = \frac{735}{840}$$

So, the descending order is $$\frac{735}{840}$$,$$\frac{600}{840}$$,$$\frac{560}{840}$$,$$\frac{504}{840}$$
This is $$\frac{7}{8}$$,$$\frac{5}{7}$$,$$\frac{2}{3}$$,$$\frac{3}{5}$$ and the correct option is option (a)