The correct answer is option 1: peat. Peat is the first stage in the formation of coal. It is formed from the accumulation of partially decayed plant material, usually in wet and swampy environments. Peat is characterized by recognizable traces of the original plant material, which can include fragments of leaves, stems, and roots.

Option 2: anthracite, is not the correct answer for this question. Anthracite is the highest rank of coal and is characterized by its high carbon content and low moisture, volatile matter, and ash content. It is a hard and glossy coal that has undergone significant heat and pressure, resulting in the loss of most of its original plant material. Therefore, it does not contain recognizable traces of the original plant material.

Option 3: bituminous coal is a medium-rank coal that falls between peat and anthracite in terms of its carbon content and heat content. It does not contain recognizable traces of the original plant material like peat does.

Option 4: lignite is a low-rank coal that forms from the accumulation of partially decayed plant material. While it is more advanced in its formation compared to peat, it still retains some recognizable traces of the original plant material. However, it