To solve this problem, we need to understand the concept of the temperature coefficient of resistance.$\\$The temperature coefficient of resistance indicates how the resistance of a material changes with temperature.$\\$• A positive temperature coefficient means resistance increases with temperature.$\\$• A negative temperature coefficient means resistance decreases with temperature.$\\$Let's analyze the given options:$\\$1. Insulators only:$\\$Insulators typically have a very high resistance and do not conduct electricity well.$\\$Their resistance does not significantly decrease with temperature, so they do not have a negative temperature coefficient.$\\$2. Semiconductors only:$\\$Semiconductors, such as silicon and germanium, have a negative temperature coefficient of resistance.$\\$As temperature increases, more charge carriers are available, decreasing resistance.$\\$3. Insulators and semiconductors:$\\$While insulators generally do not have a negative temperature coefficient, semiconductors do.$\\$However, some insulators can behave like semiconductors at higher temperatures, showing a decrease in resistance.$\\$4. Metals:$\\$Metals have a positive temperature coefficient of resistance.$\\$As temperature increases, the resistance of metals increases due to increased lattice vibrations.$\\$Therefore, the correct answer is:$\\$Option 3: Insulators and semiconductors.