Final answer:
Without specific symbols associated with the options, it's challenging to identify which symbol represents a timer motor. Generally, timer motor symbols include notations for timing functions.
Step-by-step explanation:
The symbol that represents a timer motor in a schematic or an electrical drawing can vary depending on the specific context or the standard being used. However, without the given context or specific options (symbols) associated with the letters (a, b, c, d), it's challenging to provide an accurate answer to which symbol represents a timer motor. Typically, in electrical schematics, a timer motor might be represented by a symbol that includes a box with a specific notation inside to indicate timing functions, such as a clock face or the letter 'T'.