Which statement accurately describes the chemical symbol of an element?

The chemical symbol always begins with a capital letter.

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... The chemical symbol is always a single letter.
... The chemical symbol always starts with the same letter as the name of the element.
No for both choices. 
Examples:  The chemical Symbol for silver is Ag.  For lead, it's Pb.

... The chemical symbol always begins with a capital letter.
YES

... The chemical symbol can be shared by more than one element. 
No.  Each chemical symbol refers to only one element.

The answer should be a.

The radiation of the fire causes the saucepan to heat up. the conduction of the saucepan then to distribute the heat over the saucepan and to give heat to the water. the convection of the water distributing the heat within the water, till all the water is boiling