Step 1: Understand broad spectrum antibiotics.
Broad spectrum antibiotics are effective against both Gram-positive and Gram-negative bacteria. Step 2: Analyze the given compounds.
Amoxicillin is a semi-synthetic penicillin effective against a wide range of bacteria.
Chlordiazepoxide and Meprobamate are sedatives, not antibiotics.
Penicillin (natural) has narrow spectrum activity. Step 3: Conclusion.
Amoxicillin is a broad spectrum antibiotic.