The correct option is D Barbiturates cause relaxation and temporary euphoria.
Cocaine are stimulants that is they elevate mood, increase feelings of well-being and increase energy and alertness.
Opium and morphine are powerful pain-killers. They produce a quick, intense feeling of pleasure followed by a sense of well-being and calm.
Barbiturates are depressants that slow down the normal brain function.
Thus, the correct answer is 'Barbiturates cause relaxation and temporary euphoria'.