Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage

Generation gap refers to the difference in the ways of thinking and perception in the people of two different generations which results in behavioral differences, and sometimes, (21) ______ between them. In other words, it is the difference in the thinking of the people of older and younger generations that creates the (22) ______ of understanding between them. The most common example of generation gap is seen in the family between parents and their children. It is not only because of the gap in age but also because of the way parents (23) ______ to a particular situation.

Advancement technology has led to the generation gap in this modern world. Children tend to spend most of their time with their digital devices and busy with social media that they do not discuss their problems with their parents. The Internet (24) ______ solutions to most of the problems that children needn't ask their own parents for help, (25) ______ the communication and leading to a generation gap.

Generation gap occurs not only between parents and children but also between teachers and students. Students are likely to enjoy the classes of an open-minded teacher, who shows mutual (26) ______ to the students. The teachers, who tend to keep their students under unnecessary strict disciplines and practise hard ways to make them obey the orders, are usually disliked by the students. This narrows minded thinking, especially (27) ______ in the teachers of the older generation, eventually creates a gap between the students and teachers.

Another difference is the use of technology. Young teachers tend to use more digital devices is class for their lessons that has a good (28) ______ on the students. Students take more interest and participate actively in the class discussion. An old teacher has (29) ______ - frequent use of electronic devices that makes lessons boring, which is not enjoyed by the students and it creates a gap between them.

To (30) ______ the generation gap, parents or teachers must be close to their children. They should show interest and give time to the children, have open communication, and allow the child to feel free in all the situations.