103 Let $a$ be a positive number, then the system of equations
$$
\left\{\begin{array}{l}
y=a x^{2} \\
y^{2}+3=x^{2}+4 y
\end{array}\right.
$$

has different real solutions
A. exactly four groups
B. exactly two groups
C. at least one group. The number of groups varies with the value of $a$, not a constant
D. possibly none
103 A. The number of different real solutions to the system of equations is the number of different intersection points of the parabola $y=a x^{2}$ and the hyperbola $y^{2}+3=x^{2}+4 y$. The parabola $y=a x^{2} (a>0)$ has its vertex at the origin, is symmetric about the $y$-axis, and its graph lies above the $x$-axis, opening upwards. The hyperbola $y^{2}+3=x^{2}+4 y$, or $(y-2)^{2}-x^{2}=1$, has vertices at $(0,1)$ and $(0,3)$, with the real axis on the $y$-axis and the imaginary axis on the line $y=2$. Therefore, the two graphs have 4 intersection points.