Why do we subtract D&A from EBITDA to get EBIT $($other than it being the definition$)?$

Because $D$&$A$ is neither a cash flow nor an expense for tax purposes; we must ignore it

Because, while D&A is not a cash flow, it is a tax expense, which lowers our taxes due

Because D&A is a cash flow but not an expense for tax purposes; we must ignore it

Because D&A is not an actual cash flow