The correct answer is (a) Restrictive.
The author argues that the modern environment is restrictive because it is full of rules and regulations that limit our freedom. For example, we are not allowed to drive as fast as we want, we are not allowed to build houses wherever we want, and we are not allowed to pollute the environment. These restrictions are necessary to protect us and the environment, but they can also be frustrating and inconvenient.
The other options are incorrect because they do not accurately reflect the author’s argument. Option (b), Instructive, is incorrect because the author does not argue that the modern environment is instructive. Option (c), Less developed, is incorrect because the author does not argue that the modern environment is less developed. Option (d), Impracticable, is incorrect because the author does not argue that the modern environment is impracticable.
In conclusion, the correct answer is (a) Restrictive. The author argues that the modern environment is restrictive because it is full of rules and regulations that limit our freedom.