The correct options are
A A rapidly expanding age pyramid is narrow at the base.
D A declining age pyramid is broad at the base.
A rapidly expanding age pyramid is broad at the base as the number of individuals in the pre-reproductive stage is more. In a slowly expanding age pyramid, the bar length of the pre-reproductive class is slightly larger than the bar length of reproductive class. In a stable age pyramid, the number of individuals in all age classes is quite similar. A declining age pyramid has more number of individuals in the post-reproductive stage, making the pyramid narrow at the base.