What is the order of most-to-least rapidly-scaling (fastest to scale first)?
A) EC2 + ELB + Auto Scaling

B) Lambda
C) RDS

A.
B, A, C

B.
C, B, A

C.
C, A, B

D.
A, C, B

Explanation:
Lambda is designed to scale instantly. EC2 + ELB + Auto Scaling require single-digit minutes to scale out. RDS will take
at least 15 minutes, and will apply OS patches or any other updates when applied.
https://aws.amazon.com/lambda/faqs/