Independent solution
How to solve this Duration and Convexity question
Setup
Setup
Use price convexity defined as the second yield derivative divided by price.
Model
Model
A level perpetuity has convexity two divided by yield squared, while a long zero uses its maturity factors.
Compute
Compute
Replacing yield by yield minus growth gives the growing perpetuity's larger convexity.
Answer
Answer
The order from lowest to highest is y, x, z, corresponding to choice B.