A. The Age-Sex pyramid of Australia is bell-shaped: A bell-shaped pyramid typically indicates a population with a relatively balanced distribution of age and gender. This means that there are similar proportions of males and females in different age groups. 

B. The Age-Sex pyramid of Bangladesh is wide a triangular shaped pyramid with a wide base- and is typical of less developed countries. These have larger populations in lower age groups due to high birth rates. So, the statement is wrong.

C. The Age-Sex pyramid of Nigeria is triangular shaped: A triangular-shaped pyramid is typically associated with a population with a high birth rate and a high child mortality rate. This means that there is a large proportion of young people (children and adolescents) in the population, and the pyramid tapers off towards the top because of higher mortality rates among the elderly.

D. The Age-Sex Pyramid of Japan has a narrow base and a tapered top: A pyramid with a narrow base and a tapered top is characteristic of an aging population with a lower birth rate. In Japan's case, this pyramid shape indicates a declining birth rate and a higher life expectancy, resulting in a population with a smaller proportion of young people and a larger proportion of elderly individuals.

So, the correct option is option 1.