What equation best represents the transformation of y = x^2

Horizontal shift left 3 and Vertical shift down 1

A. y = (x + 3)^ 2 - 1

B. y = (x + 1)^ 2 + 3

C. y = (x − 3)^ 2 - 1

D. y = (x − 1)^ 2 – 3​