The correct option is D.[tex]0< x\leq 20[/tex] and [tex]0< y\leq 60[/tex].
Given, [tex]x[/tex] represent the number of male birds and [tex]y[/tex] represent the number of female birds.
The flock needs to have exactly three times more females than males to thrive.
So, in equation form we have,
[tex]y=3x[/tex]........(1)
Since, The zoo only has room for a maximum of 20 male birds.
So, we can write the inequality for [tex]x[/tex] as,
[tex]0< x\leq 20[/tex]......(2)
Since The maximum number of male birds is 20, so for [tex]x=20[/tex]
y will be,
[tex]y=3\times 20\\[/tex]
[tex]y=60[/tex]
Hence, The maximum number of female birds is 60.
So, we can write the inequality for [tex]y[/tex] as,
[tex]0< y\leq 60[/tex]
Hence the required constraints are [tex]0< x\leq 20[/tex] and [tex]0< y\leq 60[/tex].
For more details on Inequality follow the link:
https://brainly.com/question/19491153