Explanation: For a TELEX call, which utilizes SITOR (SImplex Teletype Over Radio) or AMTOR (AMateur Teletype Over Radio), the transceiver must be set to an FSK (Frequency Shift Keying) emission mode. F1B is the ITU designation for direct FSK, where the carrier frequency shifts between two discrete frequencies to represent binary data. J2B mode, often implemented as AFSK (Audio Frequency Shift Keying) tones applied to an SSB (Single Sideband) transmitter, results in an equivalent FSK emission. Different manufacturers might label their SITOR-capable modes as F1B or J2B. Both effectively provide the FSK modulation required for TELEX. Option A is incorrect because J3E is the ITU designation for Single Sideband voice communication, not a digital data mode like FSK for SITOR. Option C is incorrect because ARQ (Automatic Repeat Request) and FEC (Forward Error Correction) are error correction *protocols* used within SITOR Mode A and Mode B, respectively; they are not the emission modes themselves. J3E is still an incorrect choice for the underlying emission.