Answer: Option 'B' is correct.
Step-by-step explanation:
Since we have given that
Number of female students = 1800
Number of male students = 2000
Ratio of female students to male students is given by
Female students : Male students
[tex]1800:2000\\\\=9:10\\\\=\dfrac{9}{10}[/tex]
Hence, Option 'B' is correct.