It would be A because B could be answered best with a poll graph, C with a pie graph, and D with a bar graph. Line graphs typically show speed and rate so A makes the most sense, but you are still able to do the other questions on a line graph.
I feel it is C, but I am not sure if it is correct, I can only apologize if it is wrong.
Rest your fingers gently on the home row or home keys.
Rest your palms on the keyboard.
Relax your fingers.
All the above are proper keyboard techniques apart from slouch in your chair. It is always recommended to sit up straight with your feet positioned on the floor for balance. Do not cross. Center your body to the H key and have your elbows at sides and bent about 90 degrees. Use correct fingering and deploy touch typing. These and many others will help develop optimal speed and accuracy and help prevent the development of stress injury.