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Technically "OPTION" is not a metacommand. QuickBASIC only supported "BASE" second keyword which was only to change the first subscript to dimension an array, either zero or 1, when the programmer doesn't use a statement like "DIM A(1 TO 10) AS INTEGER". The "OPTION _EXPLICIT" is a QB64-only thing; note that other BASIC's don't carry the underscore in the same statement, although there is "$NOPREFIX" metacommand to suppress the leading underscore from QB64-only keywords.
"OPTION" is recommended used near the top of the program before any executable statements and preferably before any variable is declared or created.
A metacommand, which is not compatible with Q(uick)BASIC must begin with "$" such as "$NOPREFIX", "$CONSOLE:ONLY" or "$CHECKING:OFF". The ones compatible with Q(uick)BASIC must begin with "REM" or apostrophe, then "$" then "keyword" and then it depends such as "'$INCLUDE: 'file.bi'" or "'$STATIC". Those older metacommands must be treated like remarks, not like the QB64-only ones or the compiler throws an error.
https://qb64phoenix.com/qb64wiki/index.php/Metacommand
BTW do not use double quotation marks in any of those statements for source code, it's a tendency of mine.
Technically "OPTION" is not a metacommand. QuickBASIC only supported "BASE" second keyword which was only to change the first subscript to dimension an array, either zero or 1, when the programmer doesn't use a statement like "DIM A(1 TO 10) AS INTEGER". The "OPTION _EXPLICIT" is a QB64-only thing; note that other BASIC's don't carry the underscore in the same statement, although there is "$NOPREFIX" metacommand to suppress the leading underscore from QB64-only keywords.
"OPTION" is recommended used near the top of the program before any executable statements and preferably before any variable is declared or created.
A metacommand, which is not compatible with Q(uick)BASIC must begin with "$" such as "$NOPREFIX", "$CONSOLE:ONLY" or "$CHECKING:OFF". The ones compatible with Q(uick)BASIC must begin with "REM" or apostrophe, then "$" then "keyword" and then it depends such as "'$INCLUDE: 'file.bi'" or "'$STATIC". Those older metacommands must be treated like remarks, not like the QB64-only ones or the compiler throws an error.
https://qb64phoenix.com/qb64wiki/index.php/Metacommand
BTW do not use double quotation marks in any of those statements for source code, it's a tendency of mine.