Hybrid suitability:
- Entity A (EDP, S.A.): Large regulated utility/energy company in Portugal, with extensive regulated/CESE components, high EBITDA and strong asset base, but has significant leverage and complex state involvement. Likely investment-grade around BBB region; strong cash flows from energy operations, though some regulatory charges. Could improve leverage with hybrid issuance; however, if currently near solvency tightness, refinancing could be beneficial. Overall: Strongly suitable due to infrastructure/utility profile and potential rating headroom, with strategic refinancing needs.
- Entity C (TenneT Holding B.V.): Transmission system operator, regulated infrastructure business, Dutch state-owned, with substantial hybrid capital already in place, high stable cash flows from tolls/regulated charges, strong credit profile. Very compatible with hybrid issuance to optimize capital structure and M&A/Capex funding. Likely strongly suitable, high credibility and visibility, rating headroom possible.
- Entity B (A2A S.p.A.): Energy group in Italy, diversified with activities; not as utility-regulated focus as TenneT; mixed financials with some negative pockets and smaller scale; still has stable cash flows but less infrastructure-like certainty than TenneT. Likely Marginally suitable rather than strongly.

Order: C, A, B

<answer>C,A,B</answer>