Question Analysis;
* We need exact value of the container after 360 liters of fuel were added.
* Let capacity of container = C Liters.
* Before 360 Liters of fuel was added there were N Liters of fuel in the container.
$$\cdot\ After\ 360\ Liters\ of\ fuel\ were\ added,\ amount\ of\ fuel\ in\ the\ container\ was\ \frac{5}{8}\ of\ \tan k's\ capacity.$$
$$Thus\ N\ +\ 360\ =\ \frac{5}{8}C$$

$$Statement\ 1\ =\ After\ 360\ Liters\ were\ added\ the\ container\ had\ 108\ Liters\ less\ than\ \frac{3}{4}\ of\ the\ \tan k's\ capacity.$$
From the equation we have,
$$N\ +\ 360\ =\ \frac{3}{4}C\ -\ 180$$
$$Since\ N\ +\ 360\ =\ \frac{5}{8}C\ \left(from\ the\ equation\right)$$
$$\frac{5}{8}C\ =\ \frac{3}{4}C\ -\ 180\ $$
$$\frac{5}{8}C\ -\ \frac{3}{4}C\ =-\ 180\ $$
From the equation, we can get a definite value of C, hence, statement 1 is sufficient.

Statement 2 = Before the 360 Liters were added, there were 180 Liters of fuel in the container.
* After the 360 liters were added, there were 180 + 360 = 540 Liters.
$$Since\ after\ the\ 360\ liters\ were\ added,\ the\ amount\ of\ fuel\ in\ the\ container\ was\ 5-8\ of\ the\ \tan k's\ capacity.\$$
$$We\ have\ 540\ =\ \frac{5}{8\ }C\ dividing\ both\ side\ by\ Co-efficient\ of\ C\ will\ give\ us\ a\ definite\ value.\ Hence\ statement\ 2\ is\ also\ sufficient.$$
Final answer is Option D, because statement 1 and 2 are sufficient alone.