20 moles of water:

Given: Number of moles = 20

Atomic mass of H_{2}O = 2 × 1 + 16 = 18g/mol

To find out the mass of water, apply the formula given:

Number of moles = \(\frac{Mass}{Molar\,mass}\)

⇒20 = \(\frac{mass}{18\,g/mol}\)

⇒ Mass = 20 mol × 18g/mol

⇒ Mass = 360 g

1.2044 x 10^{25} molecules of water:

1 mole = 6.022 × 10^{23}

1.2044 x 10^{25} molecules = \(\frac{1.2044\times10^{23}}{6.022\times10^{23}}\)

⇒20 moles

Mass of 20 moles of water is 360g.

**Thus, option D is correct.**