Correct Answer - Option 1 : Deepa
From the given information,
1) Tom ranked higher than Mona but did not get the highest rank.
> Tom > Mona
2) Jacob got a higher rank than Deepa but ranked lower than Mona.
Mona > Jacob > Deepa
3) Rohan got the highest rank among the students.
From statements 1& 2
Rohan > Tom > Mona > Jacob > Deepa
Hence, Deepa got the lowest rank.