A web developer has created a custom HTTP call to a backend application. The HTTP headers being sent
by the HTTP call are:
GET / HTTP/1.1
User-Agent: MyCustomApp (v1.0)
Accept: text/html
Cache-Control: no-cacheConnection: keep-alive
CookiE. somecookie=1
The backend server is responding with the following:
HTTP/1.1 400 Bad Request
DatE. Wed, 20 Jul 2012 17:22:41 GMT
Connection: close
Why is the HTTP web server responding with a HTTP 400 Bad Request?

A.
The client request does NOT include a Host header.

B.
The User-Agent header contains an invalid character.

C.
The web server is NOT expecting a keep-alive connection.

D.
The web server is configured to accept HTTP 1.0 requests only.