A system of two equations: $x^2+y^2=9$ and $y=x^2-4$ and their graphs in the 
xy-plane are shown above. How many solutions 
does the system have?
Choices:
A:One
B:Two
C:Three
D:Four
Please directly answer the question and provide the correct option letter, e.g., A, B, C, D.
Question: A system of two equations: $x^2+y^2=9$ and $y=x^2-4$ and their graphs in the 
xy-plane are shown above. How many solutions 
does the system have?
Choices:
A:One
B:Two
C:Three
D:Four
Please first conduct reasoning, and then answer the question and provide the correct option letter, e.g., A, B, C, D, at the end.
Question: A system of two equations: $x^2+y^2=9$ and $y=x^2-4$ and their graphs in the 
xy-plane are shown above. How many solutions 
does the system have?
Choices:
A:One
B:Two
C:Three
D:Four