If option strict is set to on, which of the following statements assigns the sum of two integer variables to the text property of the lbltotal control?
a) lbltotal.text = num1 + num2
b) lbltotal.text = str(num1 + num2)
c) lbltotal.text = cstr(num1 + num2)
d) lbltotal.text = convert.tostring(num1 + num2)