function OnSubmit(e) {  
  var sheet = SpreadsheetApp.getActiveSheet();
  var startRow = sheet.getLastRow()-1; 
  var numRows = 1; // Number of rows altogether


  // Fetch the range of cells A(last row):G(last row)
  var dataRange = sheet.getRange(startRow, 1, numRows, 7);

  // Fetch values for each row in the Range.
  var data = dataRange.getValues();
  for (i in data) {
   var row = data[i];
   var emailAddress = row[2];   // Column C of last row
   var message = ""; 
   while(row[6] === "") {     // Delay until data verification is done
     Utilities.sleep(10000);
   }
   var subject = row[6]  // Column G (data verification cell) of last row
   MailApp.sendEmail(emailAddress, subject, message);
  }
}