`// This constant is written in column C for rows for which an email
// has been sent successfully.
var EMAIL_SENT = 'EMAIL_SENT';

/**
 * Sends non-duplicate emails with data from the current spreadsheet.
 */
function sendEmails_w_verification() {
  var sheet = SpreadsheetApp.getActiveSheet();
  var startRow = 116; // First row of data to process
  var numColumns = 8;
  var startColumn = 1;
 // Fetch the range of cells as object
  var dataRange = sheet.getRange(startRow, startColumn,
sheet.getLastRow(), numColumns);
  // Fetch values for each row in the Range.
  var data = dataRange.getValues();
  for (var i = 0; i < data.length; ++i) {
    var row = data[i];
    var emailAddress = row[1]; // Second column
    var message = "Thank you for registering for the webinar"; // Second
column
    var emailSent = row[8]; // ninth column
    if (emailSent != EMAIL_SENT) { // Prevents sending duplicates
      var subject = 'AFWERX Webinar Reminder';
      MailApp.sendEmail(emailAddress, subject, message);
      sheet.getRange(startRow + i, 9).setValue(EMAIL_SENT);
     // Make sure the cell is updated right away in case the script is
interrupted
      SpreadsheetApp.flush();
    }
  }
}