You are designing hotel booking forms for a travel application.
The first form contains two fields in which users enter a room type and the length of stay in days. A third field displays the total cost of the room.
The second form contains a field in which users select additional-cost options such as a sight-seeing tour.
A second field displays the total cost of the options.
The third form contains a field that displays the grand total of the room and options.
Which two properties are considered source properties for the declare expression used to calculate the grand total? (Choose two.)