The correct option is A which itself had been adapted earlier
The given sentence presents a sequence of events in which one alphabet was adapted from another, and that another was adapted from a different alphabet- the Roman alphabet was adapted from the Etruscan alphabet, the Etruscan alphabet, in turn, was adapted from a western Greek alphabet, and the western Greek alphabet had been adapted from the Phoenician alphabet. The sentence uses simple past tense to state the first fact and then uses past perfect for the later two facts. This is so because the later two ideas had happened before the first one. Also, the use of past perfect to describe both the later ideas is also correct because there is no other tense with with to describe the very first event. While the use of 'itself' is confusing it is not incorrect as it just reinforces the fact that Roman alphabet is adapted from Etruscan alphabet just as the Etruscan alphabet has been adapted from a western Greek alphabet and so on. Since the sentence is essentially correct, it requires no change. Therefore, option A is the correct answer.