What is required when cooking high acid tomato sauce

True it's the strategy

The person who utilize the progression principle will keep adding the difficulty of the exercise that he's doing, while the person who does not, will only stay stagnant.  the person that utilize progression principle, will get a stronger endurance because now his body is conditioned to do harsher routines.{the answer was already on verified)

Your answer is going to be c. 

The answer would be    hot or cold holding temperatures of potentially hazardous food.