=+1. Which of the following represents drug tolerance?

a. Hans has grown to accept the fact that his wife likes to have a beer with her dinner, even though he personally does not approve of the use of alcohol.

b. Jos often wakes up with a headache that lasts until he has his morning cup of coffee.

c. Pierre enjoys the effect of marijuana and is now using the drug several times a week.

d. Jacob had to increase the dosage of his pain medication when the old dosage no longer effectively controlled the pain from his chronic back condition.

e. Chau lost his job and is now homeless as a result of his drug use.