Concept:The verb "contemplate" is followed by a gerund (verb + "-ing"), not an infinitive.
Explanation:The sentence requires a word that completes the structure "The referee contemplated ______ the players off the pitch."
The verb "contemplate" means to consider or think about doing something.
It is correctly followed by a gerund form, e.g., "contemplate doing something."
Thus, "sending" fits correctly.
Other options like "to send" or "to be sending" are infinitives and are not used after "contemplate."
Answer:C. sending
Complete sentence: "The referee contemplated sending the players off the pitch."