Final answer:
The normal gestation length for a gerbil is typically between 24 and 26 days, making option c) 26-29 days the closest available choice.
Step-by-step explanation:
The normal gestation length for a gerbil is 24 to 26 days. This means that option (c) 26-29 days would be the closest choice listed, although it is slightly longer than the typical range.
Just like in humans, where gestation lasts about 266 days, and in animals like dogs and cats with an average of 60 days, the gestation period can vary slightly from one individual to another. However, gerbil pregnancies are generally short compared to the gestation periods of other animals.