Use the following information to answer the questions below. A few decades ago,Knudsen and colleagues proposed a theory that,for a normal cell to become a cancer cell,a minimum of two genetic changes had to occur in that cell.Knudsen was studying retinoblastoma,a childhood cancer of the eye. -Which of the following types of mutation would convert a proto-oncogene into an oncogene?
A)a mutation that blocks transcription of the proto-oncogene B)a mutation that creates an unstable proto-oncogene mRNA C)a mutation that greatly increases the amount of the proto-oncogene protein D)a deletion of most of the proto-oncogene coding sequence E)a deletion of the 5' upstream region of the proto-oncogene coding sequence