What option should an Architect recommend to enable the Heroku application to use wkhtmltopdf?

A financial reporting application, hosted on an on-premise server, uses a native library (wkhtmltopdf) to convert its HTML reports into PDFs. The app is being migrated to Heroku.

What option should an Architect recommend to enable the Heroku application to use wkhtmltopdf?
A . Ensure that the Heroku app fetches the wkhtmltopdf library from cloud storage on dyno restart.
B . Install the dependency using sudo apt install wkhtmltopdf from .profile in the project root.
C . Continue to host wkhtmltopdf on-premise, and build a REST API so the library can be invoked from the Heroku app.
D . Use a custom buildpack to install wkhtmltopdf using apt.

Answer: D