1. Identify the elements from their atomic numbers

• $32 \rightarrow \text{Ge (Germanium)}$
• $35 \rightarrow \text{Br (Bromine)}$
• $19 \rightarrow \text{K (Potassium)}$
• $87 \rightarrow \text{Fr (Francium)}$

2. Recall the trend of first ionisation enthalpy

First ionisation enthalpy generally:

• increases across a period from left to right,
• decreases down a group from top to bottom.

So, elements lying more toward the bottom-left of the periodic table have the lowest first ionisation enthalpy.

3. Compare the given elements

• Ge and Br are in higher periods and more to the right, so their ionisation enthalpies are relatively high.
• K is an alkali metal, so it has low ionisation enthalpy.
• Fr is also an alkali metal and lies below K in the same general trend, so its first ionisation enthalpy is even lower.

Thus, $\text{Fr} < \text{K} < \text{Ge, Br} \quad \text{in first ionisation enthalpy}.$

4. Select the correct option

The element with atomic number $87$ has the lowest first ionisation enthalpy.

Therefore, the correct answer is: $\boxed{87}$ which corresponds to Option D.