assume the co-ordinates of S are (x,y).
considering each option alone:
1) given: slope of OS = 1/3 and co-ordinates of O and T are (0,0)and(5,0) respectively.
OS slope is 1/3
slope of line when given two points(m) = (y1 - y2)/(x1 - x2)
so, we will get the line equation of OS. the point can be any point on the line.
so with the option 1, we can`t get the exact point.
2) given: slope of ST = 1/2 and co-ordinates of O and T are (0,0)and(5,0) respectively.
we will get the line equation of ST.
so with the option 2 also, we can`t get the exact point.
combining 1 and 2, we have two different lines (as their slopes are different), they will meet at exactly one point.
hence, it can be answered using both the options