Refer to figures.
Important to remember:

• The TO/FROM indicator is determined by the instrument:
  • If the actual radial the aircraft is on is within 90° of the selected course, the indicator will show "FROM."
  • If the actual radial is more than 90º from the selected course, the indicator will show "TO."

If we look at the question, it tells us very important facts; the new selected course (040) and the radial the aircraft is on (240). From this we can immediately see that the two radials (selected course and aircraft radial) are more than 90° apart - we will have a TO flag. This immediately eliminates two answers.

We now need to work out where the deviation indicator (needle) will be. If we draw the 040 radial, its reciprocal (220) and the 240 radial, we should have something like shown in the figure. The needle position on the instrument will depend on the instrument you are looking at.

A CDI has no heading input at all, and will simply show the selected course at the top of the instrument and the deviation needle will indicate how far away the required radial is to the left or right (to a maximum 10°). If TO is showing (which in this case it would be), then the VOR will show you indications as if you were flying TO the VOR. In this instance it would show 10° (full scale deflection) right deviation, as heading is irrelevant when using a CDI. It is only concerned with selected CRS and deviation. (If you wanted correct sensing in this case, you should have selected 220 FROM, which would then show the needle 10° to the left. However for whatever reason the pilot has selected TO when flying away from the VOR, which results in reverse sensing.)

A HSI is basically a normal direction indicator with a rotating CDI located in the centre. As the pilot changes the selected course, the rotating CDI moves to point in the actual direction of that selected course. The CDI works precisely the same as a normal fixed CDI, but it can be displayed in any orientation, and therefore can be upside down. As long as the pilots are aware of this, it is very useful, allowing for correct sensing indications even when facing the wrong way, such as a backcourse ILS, or a situation such as this where you are flying away from a VOR but with a radial on the opposite side of the VOR selected.

Heading IS relevant on a HSI as it will always indicate in the correct sense. On the HSI, you will still have a TO flag, but you will now have the correct sensing indication of 10° left deviation. The logical turn in this case would be to the left, as the required radial is on your left by 20°.

Note. The TO flag does not always point up, it points towards the selected course - in this case 040 is behind the aircraft so the TO flag will also point behind the aircraft. On the HSI this is important to remember!