You will be given a definition of a task first, then some input of the task.
In this task, you're given a question, along with a context passage. The passage will not have a direct answer to the question, but can include some information and a clue for the answer. Assuming you can only obtain information about one entity in the passage, your job is to determine whether information from the passage can be used to answer the question. Indicate your choice as `a` for Yes or `b` for No.

Question: When did the Sassanids replace the Parthians? Passage:In 270 the Roman emperor Aurelian engaged the Sassanids, who had now replaced the Parthians, on the eastern front and he was able to drive them back. Tiridates, as the true heir to the now Persian-occupied Armenian throne, came to Armenia and quickly raised an army and drove the enemy out in 287. When Tiridates returned to Armenia, he made the city of Vagharshapat his capital, as it had been the capital of his late father. For a while, fortune appeared to favour Tiridates. He not only expelled his enemies, but he carried his arms into Assyria. At the time the Persian Empire was in a distracted state. The throne was disputed by the ambition of two contending brothers, Hormuz and Narses. The civil war was, however, soon terminated and Narses was universally acknowledged as King of Persia. Narses then directed his whole force against the foreign enemy. The contest then became too unequal. Tiridates once more took refuge with the Romans. The Roman-Armenian alliance grew stronger, especially while Diocletian ruled the empire. This can be attributed to the upbringing of Tiridates, the consistent Persian aggressions and the murder of his father by Anak. With Diocletian's help, Tiridates pushed the Persians out of Armenia. In 299, Diocletian left the Armenian state in a quasi-independent and protectorate status possibly to use it as a buffer in case of a Persian attack. Tiridates married an Alani Princess called Ashkhen in 297 by whom he had three children: a son called Khosrov III, a daughter called Salome and an unnamed daughter who married St. Husik I, one of the earlier Catholicoi of the Armenian Apostolic Church.

Output:
b