Regex Wizardry: Level 2

Welcome to the next level of regex wizardry! You've mastered the basics, now it's time to tackle some more advanced patterns. Think you're ready?

Challenge 1: Match All the Things!

Write a regex to match all the words that start with the letter 'a' or 'A' in the string "The quick brown fox jumps over the lazy cat."

Challenge 2: Find the Secret Message!

A clever regex master will be able to decode the following message:

[base64 encoded string here]

Challenge 3: Regular Expression Jenga

Remove all occurrences of the word 'cat' from the string "cat cat cat" using only a single regex pattern!

Don't say you didn't know this was coming...