The Kyoto Protocol, an international agreement aimed at combating climate change, requires developed nations to reduce their emissions of greenhouse gases. This reduction target is set for the years 2008-2012.

Option 1 states that the commitment is to reduce emissions by an average of 4% below 1990 levels. This means that countries would aim to emit 4% less greenhouse gases than what they emitted in 1990.

Option 2 suggests a reduction target of an average of 5% below 2000 levels. This means that countries would aim to emit 5% less greenhouse gases than what they emitted in 2000.

Option 3 states a commitment of an average of 4.2% below 2000 levels. This implies that countries would aim to emit 4.2% less greenhouse gases than what they emitted in 2000.

The correct answer, option 4, states a commitment of an average of 5.2% below 1990 levels. This means that countries would aim to emit 5.2% less greenhouse gases than what they emitted in 1990.

Therefore, the correct answer is option 4.