I have the following 3 strings...

```
a = "The URL is www.google.com"
b = "The URL is google.com"
c = "The URL is http://www.google.com"

```

Ruby's URI extract method only returns the URL in the third string, because it contains the http part.

```
URI.extract(a)
=> []

URI.extract(b)
=> []

URI.extract(c)
=> ["http://www.google.com"]

```

How can I create a method to detect and return the URL in all 3 instances?