1. Identify the element referred to in the question

   The apatite family mainly contains phosphate minerals. Hence, the main component involved is phosphorus.

   So we need the first ionisation enthalpy of phosphorus.

2. Recall the first four elements of group 15

   Group 15 elements are: $\text{N, P, As, Sb}$

   Their approximate first ionisation enthalpies are:

   • Nitrogen: $1402\ \text{kJ mol}^{-1}$
   • Phosphorus: $1012\ \text{kJ mol}^{-1}$
   • Arsenic: $947\ \text{kJ mol}^{-1}$
   • Antimony: $834\ \text{kJ mol}^{-1}$

3. Match phosphorus with the given options

   For phosphorus, the value is: $1012\ \text{kJ mol}^{-1}$

   This corresponds to Option D.

4. Check all options

   • A: 834 kJ mol$^{-1}$ $\to$ corresponds to Sb, not P
   • B: 947 kJ mol$^{-1}$ $\to$ corresponds to As, not P
   • C: 1402 kJ mol$^{-1}$ $\to$ corresponds to N, not P
   • D: 1012 kJ mol$^{-1}$ $\to$ corresponds to P

Therefore, the correct answer is D.