In the final examination, Bishnu scored 52% and Asha scored 64%. The marks obtained by Bishnu is 23 less, and that by Asha is 34 more than the marks obtained by Ramesh. The marks obtained by Geeta, who scored 84%, is

The correct option is 399.

Let the total marks in the examination be represented by $T$ and the marks obtained by Ramesh be represented by $R$.

According to the problem, Bishnu scored 52% of the total marks, and this score is 23 marks less than Ramesh's marks. We can write this as an equation:
$0.52T=R-23$
Rearranging this to express Ramesh's marks in terms of the total marks gives:
$R=0.52T+23$     (Equation 1)

Similarly, Asha scored 64% of the total marks, which is 34 marks more than Ramesh's marks. This gives the following equation:
$0.64T=R+34$
Rearranging this to express Ramesh's marks gives:
$R=0.64T-34$     (Equation 2)

Since both equations represent Ramesh's marks ($R$), we can equate the two expressions:
$0.52T+23=0.64T-34$

Subtracting $0.52T$ from both sides and adding 34 to both sides:
$23+34=0.64T-0.52T$
$57=0.12T$

Solving for $T$:
$T=\frac{57}{0.12}=\frac{5700}{12}=475$
So, the total marks in the examination are 475.

Geeta scored 84% of the total marks. We calculate Geeta's marks as follows:
$\text{Geeta's Marks}=84\%\text{of}T$
$\text{Geeta's Marks}=0.84\times 475$
$\text{Geeta's Marks}=\frac{84}{100}\times 475$
$\text{Geeta's Marks}=21\times 19=399$

Therefore, the marks obtained by Geeta is 399.