The demand curve for fire extinguishers in Wakanda slopsdownward and the supply curve for fire extinguishers in Wakandaslops upward. The production of the 150th fire extinguisher entailsthe following:

• a private cost of $10;
• an external cost of $1;
• a private value of $9;
• an external benefit of $3.

Is the socially-optimal quantity of fire extinguishers inWakanda less than, equal to, or greater than 150? Brieflyexplain.