The first Secretary General of the Commonwealth served for a period of ......... years.

Analyze the question: It asks how long the first Secretary-General of the Commonwealth held office.

Concept: The Commonwealth Secretariat was set up in 1965, and the post of Secretary-General was created at that time. The first holder was Arnold Smith, a Canadian diplomat.

Working:

• Arnold Smith took office in 1965.
• He served until 1975, when Sir Shridath Ramphal of Guyana succeeded him.
• Period of service: 1975 − 1965 = 10 years.

Why the other options are wrong:

• 5 years is too short. Smith served two terms.
• 15, 20 and 25 years are too long. Later Secretaries-General such as Ramphal served about 15 years (1975–1990), so don't confuse the two.

Tip: Remember "Smith 65–75, Ramphal 75–90." The first Secretary-General served a decade, and the second served 15 years. In the exam, link each name to its dates.