how do you bid this hand?

Matchpoints, white/red, RHO deals and passes.  You are playing 15-17
1NT.  For an auction 1m:1M:1NT, you have a version of 2-way checkback
where 2C forces 2D.  You hold

Kx  AJ  KT9xxx  Kxx

Question 1.  Do you open 1D or 1NT ?

Suppose you open 1D.  Pard replies 1H.  Opps are passing throughout.

Question 2:  Do you rebid 1NT or 2D?

Suppose you rebid 1NT.  Pard now bids 2C, you dutifully bid 2D, and
pard bids 2H, showing, in your dialect, exactly 5 hearts,
invitational, and saying nothing else about shape.

What do you bid?

TIA..

David