a) Implement conditional formatting to show that if the total spent before VAT is £1000 or more, the cell will be highlighted in red to show that discount has been earned.

b) In addition, implement conditional formatting in one more suitable location in your worksheet.

c) Create an Invoice from the data entered onto the Order sheet using cell linking techniques. Then include a button on your Order Sheet to view the invoice and one on the Invoice sheet to print it.

d) The spreadsheet model must now demonstrate professional, formal layout and be user friendly. Ensure it is suitably formatted.