Tune Tones Instrument Tuning Company owes Mandy Lynn's Music Studio $5,046 as of November 1. During November, Tune Tones purchased merchandise from Mandy Lynn totaling $8,685 and made payments on account to Mandy Lynn in the amount of $7,440. The amount Tune Tones owes Mandy Lynn on November 30 is:

The prebisch–singer hypothesis concludes that: a. technology lowers the cost of manufactured products, so developing countries should see an increase in their terms of trade. b. developing countries experience a long-run decline in their terms of trade, as the demand for primary products in higher-income countries declines relative to their demand for manufactured goods. c. because of unfair trading practices, labor in developing countries is exploited. d. opec has been responsible for a slowdown in the world's standard of living.