The formula of silver phosphate is:A. \[AgP{O_4}\] B. \[A{g_3}P{O_4}\]C. \[A{g_2}{(P{O_4})_3}\]D. \[A{g_2}P{O_4}\]

To find the correct formula for silver phosphate, we need to consider the charges of the ions that make up this compound.

1. **Identify the ions:**
- Silver (\(Ag\)) typically forms a cation with a \(+1\) charge, represented as \(Ag^+\).
- Phosphate is a polyatomic anion with the formula \(PO_4^{3-}\) and has a \(3-\) charge.

2. **Determine the ratio of ions to balance charges:**
- Since the silver ion has a \(+1\) charge (\(Ag^+\)) and the phosphate ion has a \(3-\) charge (\(PO_4^{3-}\)), we need three \(Ag^+\) ions to balance one \(PO_4^{3-}\) ion.

3. **Write the chemical formula:**
- To balance the total charge, three silver ions (\(3 \times +1 = +3\)) are needed for each phosphate ion (\(-3\)). This gives us the chemical formula \(Ag_3PO_4\).

Therefore, the correct formula for silver phosphate is:

\[
\boxed{Ag_3PO_4}
\]

**Answer: Option B. \(Ag_3PO_4\)**.