The correct answer is 0.014467 M.
Molarity is defined as the number of moles present in a liter solution, that is, number of moles / liter solution.
The molar mass of sodium (Na) is 23.0 g/mol
Thus, 1 mole of Na contains 23.0 g
Now, x moles of Na contains 0.50 g
Moles = 0.50 × 1 / 23.0
Moles = 0.50 / 23.0
= 0.0217 moles of Na
Molarity = Number of moles / liters of solution
= 0.0217 / 1.5
= 0.014467 M