<u>Answer:</u> The correct answer is Option B.
<u>Explanation:</u>
To calculate the molarity of solution, we use the equation:
.......(1)
Molarity of calcium phosphate solution = 0.100 M
Volume of solution = 2.00 L
Putting values in equation 1, we get:

Moles of calcium phosphate = 0.200 moles
1 mole of calcium phosphate contains 3 moles of calcium atoms, 2 moles of phosphate atoms and 8 moles of oxygen atoms.
So, 0.200 moles of calcium phosphate will contain =
moles of oxygen atoms.
Moles of oxygen atoms = 1.6 moles
Molarity of calcium phosphate solution = 0.100 M
Volume of solution = 1.00 L
Putting values in equation 1, we get:

Moles of calcium ions =
moles
Molarity of calcium phosphate solution = 0.100 M
Volume of solution = 5.00 L
Putting values in equation 1, we get:

Moles of phosphorus atoms =
moles
According to mole concept:
1 mole of a compound contains
number of atoms
Number of phosphorus atoms in 0.500 moles of calcium phosphate will be = 
1 mole of calcium phosphate contains 3 moles of calcium ions and 2 moles of phosphate ions.
So, 0.200 moles of calcium phosphate will contain =
moles of calcium ions
Moles of calcium ions = 0.600 moles
Hence, the correct answer is Option B.