Which of the following statements is true about PSK31?

PSK31 uses a specialized character encoding called 'Varicode.' Similar to Morse code, Varicode assigns shorter bit sequences to frequently used characters to increase overall typing speed. In standard English text, lower case letters are used much more often than upper case letters. Because of this statistical frequency, Varicode assigns shorter bit sequences to lower case letters and significantly longer sequences to upper case letters. Consequently, typing a message in ALL CAPS will force the transmission of many longer bit sequences, ultimately slowing down the transmission rate. Other options are incorrect because PSK31 does not inherently use forward error correction (FEC), nor does it change transmit power based on text case. It operates very efficiently at low power compared to traditional RTTY.