What is the best definition for the word dotage?

The term "dotage" specifically refers to a state of mental decline that often accompanies old age, characterized by a lack of mental acuity and an overall decrease in cognitive function. This definition aligns perfectly with the concept of senility, which describes the condition of being senile or showing the weaknesses or diseases of old age, especially related to memory and cognition. In the context of the options provided, this understanding highlights how dotage explains the mental deterioration commonly associated with aging, making senility the most appropriate choice for its definition. Other options like strength, balance, and position do not relate to the concept of aging or mental decline, further reinforcing that senility accurately captures the essence of dotage.