The correct answer is A.

By looking only at satellite imagery, the system seems to deepen as it tracks from eastern Botswana on 16 January towards the north-western corner of Botswana, on the border with Namibia. This is seen by how the cloud type changes from a more stratiform type on 16 January to much thicker, larger and deeper convective clouds on 17 January. During this time, the central vortex of the tropical low becomes very clearly identifiable. Once the system starts tracking back towards central Botswana on 18 January, the amount of convective cloud seems to decrease and the central vortex of the storm is no longer as clear.
The deepning or filling of the low is hard to tell from a satellite image alone, as there is a strong diurnal cycle in cloudiness. When determining the strength or intensity of a system such as this, it’s important to use ground-based pressure readings to determine whether the central pressure of the system is increasing or decreasing.