What is the chemical formula of Calcium Phosphate.

The given ionic compound is calcium phosphate. It is known that calcium has a -2 charge, or that the calcium ion is written as ${\text{Ca}}^{+2}$
Similarly, the phosphate ion has a net -3 charge and is denoted as ${\left({\text{PO}}_4\right)}_3$.
Now, for a specific ionic compound representation in the criss-cross representation concept. If the ions involved are Ax and By, the chemical representation of the possible ionic compound formed is ${\mathrm{A}}_{\mathrm{y}}{\mathrm{B}}_{\mathrm{x}}$.

As a result, the chemical formula for the aforementioned ionic radical options would be ${\text{Ca}}_3{\left({\text{PO}}_4\right)}_2$.
It is important to understand where the Calcium Phosphate comes from. They are members of the family of materials or minerals that contain calcium ions and inorganic phosphate anions, as previously mentioned. When ${\text{Ca}}^{+2}$ is combined with phosphate as described above, ${\text{H}}_2{\text{PO}}_4$ and ${\text{H(PO}}_4{\text{)}}_2$, the resulting compounds are Calcium Phosphate, monocalcium phosphate, and dicalcium phosphate, respectively.

Hence, the correct option is (B).