What is the formula for the maximum active power in the cylindrical rotor synchronous machine? (Eb represents armature emf, Vt represents terminal voltage, δ represents rotor angle, X represents reactance)

• A. Eb×Vt×sinδ÷X
• B. Eb×Vt2÷X
• C. Eb2×Vt×sinδ÷X
• D. Eb×Vt÷X