$1.$ For the following statements select $($ T or F $)$ and provide a brief explanation why.

a$.$ Backtracking search for CSP is just depth first search with forward checking. $($T or F$)$

b$.$ Forward checking is a special case of constraint propagation. $($T or F $)$

c$.$ MRV is a scheme to order domain values before assigning them to a variable. $($T or F$)$

d$.$ AC$-3$ is an algorithm for ordering variables when performing backtracking search. $($ T or F$).$