First, convert BEM and crew items into moment index.
Thus, is consistent.
Crew added index = 114.8 – 112.4 = 2.4. Then 2.4 = (410 × arm)/CF → CF = (410 × 142)/2.4 ≈ 24,258 — not round.
? No — wrong; Index is not average.
Given the options, correct calculation is:
Total DOI = BEM index + Crew Index = 112.4 + 5.8 = ? That doesn’t match any option — contradiction.
Given BEM index = 112.4 at 34,560 kg. Crew: Mass 410 kg, arm 142.0. To add index, use: Added Index = (Mass × Arm) / (Reference constant) ? Wait — in EASA questions, often the index is a simple moment / 1000 or moment / 100,000 . We must deduce the Index Unit (IU).
Actually: only if index units are moment/constant and the constant is the same. Let’s test option a: DOI 114.8.