Which of these statements concerning existence and uniqueness of $y(t)$ are true?

A

If $f$ and ${\partial f \over \partial y}$ are continuous in a rectangle $|t|\leq a$ and $|y| \leq b$, then there is some interval $|t| \leq h \leq a$ in which there exists a unique solution

B

If ${\partial f \over \partial y}$ is continuous in a rectangle $|t|\leq a$ and $|y| \leq b$, then there is some interval $|t| \leq h \leq a$ in which there exists a unique solution

C

If $f$ is continuous in a rectangle $|t|\leq a$ and $|y| \leq b$, then there is some interval $|t| \leq h \leq a$ in which there exists a unique solution

D

If $f$ and ${\partial f \over \partial y}$ are continuous in a rectangle $|t|\leq a$ and $|y| \leq b$, then there exists a unique solution for all $-\infty < t < \infty$