GMAT Critical Reasoning (CR) | Re: Classical musical instruments are very complex and demand a lot of

Classical musical instruments are very complex and demand a lot of practice and theoretical knowledge to master. To a child, learning the intricacies of such an instrument is very challenging and because of the concentration needed, most children will tire fairly quickly. Since this leads to a slow learning pace, strict discipline should be maintained to avoid wasting time when teaching children how to play such musical instruments.

Which of the following, if true, calls the argument's conclusion