Final answer:
Frederick Griffith is known for discovering the process of transformation in bacteria during his experiments with Streptococcus pneumoniae.
Step-by-step explanation:
Frederick Griffith discovered transformation, which is the correct answer A) to the question. In 1928, Griffith conducted experiments with Streptococcus pneumoniae, where he demonstrated that nonpathogenic bacteria could become pathogenic by absorbing DNA from heat-killed pathogenic bacteria. This transforming principle was later determined to be DNA, which is responsible for heredity. The process of transformation is a mechanism of horizontal gene transfer that plays a role in the spread of characteristics such as antibiotic resistance within a bacterial population.