The long-run supply curve would be perfectly elastic in: O a decreasing-cost industry. O an increasing-cost industry. O a variable-cost industry. O a constant-cost industry.The "invisible hand" concept suggests that: A market failures imply the need for a national economic plan. A big businesses are inherently more efficient than small businesses. A the competitiveness of a capitalistic market economy invariably diminishes over time. A given competition, private and public interests tend to coincide