Show custom message field based on select list value

//Hides the message custome fields
lfHide("customfield_14827");
lfHide("customfield_14828");
lfHide("customfield_14829");

//Disabled the message custome fields
lfDisable("customfield_14827");
lfDisable("customfield_14828");
lfDisable("customfield_14829");

lfWatch("customfield_14824", {"customfield_14824"}, 
"/var/atlassian/application-data/jira/silprograms/Live/messageScript.sil"
 , {"change"});

//lfGlobalMessage("The live field is working!", "INFO");

if (contains(argv["customfield_14824"], "A")) {
    lfShow("customfield_14827");
    lfSet("customfield_14827", "The value of ABC is A");

lfHide("customfield_14828");
lfSet("customfield_14828", "");

lfHide("customfield_14829");
lfSet("customfield_14829", "");

}
else if (contains(argv["customfield_14824"], "B")) {
    lfHide("customfield_14827");
    lfSet("customfield_14827", "");

lfShow("customfield_14828");
lfSet("customfield_14828", "The value of ABC is B");

lfHide("customfield_14829");
lfSet("customfield_14829", "");

}
else if (contains(argv["customfield_14824"], "C")) {
    lfHide("customfield_14827");
    lfSet("customfield_14827", "");

lfHide("customfield_14828");
lfSet("customfield_14828", "");

lfShow("customfield_14829");
lfSet("customfield_14829", "The value of ABC is C");

}
else {
    lfHide("customfield_14827");
    lfSet("customfield_14827", "");