The correct option is (C):A live orchestra
Synchronised means to operate at the same time or in harmony with others. When we say something is synchronised, it indicates a level of coordination and timing.
The human body: Various systems (like the circulatory and respiratory systems) work synchronously to maintain health, which matches the idea of harmony.
A choreographer: This person organizes and coordinates dance movements, ensuring that all dancers move in harmony, making this option relevant to the meaning of synchronised.
A flock of birds: Birds flying in formation often do so in synchronisation, maintaining harmony in their movements.
A live orchestra: While an orchestra does play music together, the term "live orchestra" itself doesn’t inherently convey the concept of synchronisation. An orchestra can perform music with varying degrees of synchronisation depending on the conductor and the musicians. Thus, it is the least directly related to the meaning of "synchronised."
So, "A live orchestra" does not match the meaning of "synchronised" as strongly as the other options, which all imply a clear sense of harmony or coordinated movement.