a) 9 units
b) $$3\sqrt 3 $$ units
c) Data inadequate
d) 12 units

Answer: c
Explanation:

$$\eqalign{ & \tan {45^ \circ } = \frac{{SR}}{{QR}} \cr & \tan {30^ \circ } = \frac{{SR}}{{PR}} = \frac{{SR}}{{\left( {PQ + QR} \right)}} \cr} $$
Two equations and 3 variables. Hence we can not find the required value with the given data.
(Note that if one of SR, PQ, QR is known, this becomes two equations and two variables and if that was the case, we could have found out the required value.)