Final answer:
The correct word to complete the sentence is 'tanque'.
Step-by-step explanation:
The correct word to complete the sentence is tanque. In the sentence, the speaker's father is putting gasoline in the tanque (tank) of the car before going on a trip. The other options, gato (cat), bocina (horn), and volante (steering wheel), are not related to putting gasoline in the car.
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