Let the image of parabola \( x^{2}=4y \) in the line \( x-y=1 \) be \( (y+a)^{2}=b(x-c) \), \( a,b,c \in \mathbb{N} \). Then \( a+b+c \) is equal to:
\(12\)
\(8\)
\(6\)
\(4\)