Unique combinations of transcription factors in given cell types profile individual cell types and distinguish them, one from the next. This is essentially a cellular "barcode" for a given cell type, such that a specific combination of transcription activators turn on genes specific for that cell type. In the chart below, 5 different transcription factors are shown in the left column, and 8 different unidentified cell types (a-h) are indicated in the top row. Transcription of liver-specific genes require both transcription factors HNF1 and HNF3 to be expressed in those cells. From the pattern of expression of the transcription factors in the chart, which of the 8 cell types shown (i.e., a-h) would activate liver-specific transcription? You may choose one or more answers, and explain why you made that choice(s). Cell type