To solve this problem, we need to determine the volume of a spherical container with a given radius and compare it to the capacity in litres. Let's proceed step by step:

1. First, understand the volume of the given cube:
   • Volume of a cube = \(a^3\), where \(a\) is the side length. Here, \(a = 10 \, \text{cm}\).
   • Volume of the cube = \(10^3 = 1000 \, \text{cm}^3\).
2. 1 litre of water is equivalent to 1000 cm³.
   • This means a cube with each side 10 cm can hold exactly 1 litre.
3. Now, calculate the volume of the spherical container:
   • Formula for volume of a sphere = \(\frac{4}{3} \pi r^3\), where \(r\) is the radius.
   • Here, \(r = 10.5 \, \text{cm}\).
   • Volume of the sphere = \(\frac{4}{3} \times \pi \times (10.5)^3\).
4. Calculating this:
   • \((10.5)^3 = 1157.625\)
   • Volume = \(\frac{4}{3} \times 3.14159 \times 1157.625 \approx 4869.06 \, \text{cm}^3\).
5. Convert this volume into litres by dividing by 1000 (since 1 litre = 1000 cm³):
   • Volume in litres ≈ \(\frac{4869.06}{1000} = 4.86906 \, \text{litres}\).
6. Finally, determine which option matches this volume:
   • 4.86906 litres is more than 4.5 litres but less than 5 litres.

Thus, the correct answer is: more than 4.5 litres but less than 5 litres of water.