Visual aids are the mediums used alongside verbal descriptions to help in better understanding. Visual aids can be in different forms like graphs, video clips, charts, photographs, etc.
In the given scenario, the air conditioning manufacturing plant manager's desire to train the service installers will be best aided by the use of objects. This s because using objects will enable the trainees to be familiar with the parts and steps required for a successful installation.
The answer is A. relative. The sentence use the pronoun "that" which can be either a relative or a demonstrative. By analysing the sentence, we can see the pronoun was used to connect (relative) instead of to point at things (demonstrative).
