8. Drugs that are most likely to increase risk of infection with HIV include a. meth and LSD. b. tranquilizers and DXM. c. peyote and psilocybin. d. cocaine and heroin. d a b C

## Step 1<br />The problem is asking us to identify which drugs among the given options are most likely to increase the risk of HIV infection. HIV is a virus that is primarily transmitted through sexual contact and sharing needles among intravenous drug users.<br /><br />## Step 2<br />We need to consider the nature of each drug and its potential to increase the risk of HIV transmission. <br /><br />## Step 3<br />Meth and both drugs that can impair judgment and lead to risky behaviors, but they do not directly increase the risk of HIV transmission.<br /><br />## Step 4<br />Tranquilizers and DXM are not known to increase the risk of HIV transmission.<br /><br />## Step 5<br />Peyote and psilocybin are both hallucinogenic drugs that can impair judgment and lead to risky behaviors, but they do not directly increase the risk of HIV transmission.<br /><br />## Step 6<br />Cocaine and heroin are both drugs that can be used intravenously, which can lead to sharing needles among users. This is a known method of HIV transmission.