Which of the following statements are true? A. Semiconductors have resistivity values that are larger than those of insulators. B. Good conductors of electricity have larger conductivity values than insulators. C. A material that obeys Ohm's law reasonably well is called an ohmic conductor or a linear conductor. D. The resistance of a conductor is proportional to the conductivity of the material of which the conductor is composed. E. The resistance of a conductor is proportional to the resistivity of the material of which the conductor is composed.

Materials can be classified as conductors, semiconductors and insulators, based on their resistance and conductivity to the electric field. Conductors are mostly conductive in nature and so the electrons will be moving freely. Conductors have less resistance and more electrical conductance. So its resistance is directly proportional to the resistivity of the material of which the conductor is composed. So the option E is correct.

Then semiconductors have higher resistance compared to conductors but less resistance compared to insulators. So the first option is false that semiconductors have more resistance than insulators.

Similarly, the good conductors have good conductivity values than insulators as the insulators are not at all conductive in nature. So the option B is also correct.

Then the option C stating that material that obey ohm's law is termed as ohmic conductor or linear conductor is true. This is because, the ohm's law is true for those cases only and not for all cases.

Also the option D is false as the resistance of a conductor is directly proportional to the resistivity and inversely proportional to the conductivity.

Thus, the option B,C and E are true.