Which sentence would be the most appropriate to precede sentence (1)?

Directions for the question:

The following passage is an early draft of an essay. Some parts of the passage need to be rewritten. Read the passage and select the best answer for the question that follows. Keep in mind that some questions are about particular sentences or parts of sentences and ask you to improve sentence structure or word choice. Other questions ask to consider organization and development. In choosing the answer, follow the requirements of standard written English.

(1) Students at present are not what they were two generations ago. (2) A sense of frustration has assailed their minds. (3) They feel that the so called education does not enable them to face the economic difficulties of the modern world. (4) Hence they develop a philosophy of pessimism resulting in defiance. (5) Greater emphasis is laid upon political than upon academic interests. (6) What is still more harmful is that politicians are exploiting this non-academic interest of the students. (7) Naturally they lose their balance of mind and drift rudderless on the current of their impulses. (8) Sometimes they are misled by teacher – politicians. (9) But we need not be depressed. (10) Most of the students are yet in their teens. (11) Their minds are plastic and their hearts sensitive and impressionable. (12) If worthy ideals are set before them by teachers, guardians and other well wishers there is no reason why students should not become good useful citizens.