Answer:
A. Israel Philharmonic Orchestra
Explanation:
The Boston Philharmonic orchestra, principally. In later years he was the longtime conductor of the New York Philharmonic. He has also guest conducted the London Symphony Orchestra (LSO) (of which he was the president until 1990), The Vienna Philharmonic, and the Berlin Philharmonic. These were among the orchestras he was most frequently invited to conduct.
