Now you would like to compete, and with a normal partner a T/O would be fine. Partner would pass with a decent hand and 4♠, but it looks like partner could be 3-5 in the majors, and he could bid 3♥s.
Now for the bot D is biddable ♠.
Trying to find a competitive bid I looked at the explanation of 3♣, and it was explained as 5+♠ :-)