Answer:
The answer is E) 1 and 2
Explanation:
Given that s and t are greater than 1.
Let's assume that s = 4 and t = 2 and n = 8 (each on is a factor of the integer 8)

Now check for the options -
1)
( Can be a factor of
)
2)
( Can be a factor of
)
3)
( Cannot be a factor of
)
Thus, the option is E