Question

use of a jack stand
always place a jack stand(s) under a jacked - up vehicle. the jack stand takes the vehicle load, if the jack fails to support the vehicle, protecting the person working on the vehicle from being injured.
check to ensure the floor is suitable to use a jack and stands. the floor should be level and firm; so the risk of the vehicle falling or sinking is minimal.
position the jack stand under a load bearing part of the chassis. neglecting this might cause the cup of the jack stand to damage the vehicle; as well as cause the vehicle to be unstable.
if the suitability of a jacking/support point is in question, consult the vehicle service information.
what should you do if you have doubts about the suitability of the jacking points?
push against the selected jacking points firmly with your hand.
consult the vehicle service information.
gently tap the selected jacking points with a hammer.
check

Explanation:

The text clearly states that if the suitability of a jacking/support point is in question, one should consult the vehicle service information. Pushing against the points with a hand or tapping with a hammer are not mentioned as appropriate actions in case of doubt.

Answer:

Consult the vehicle service information.