1NT.
When we are in the protective position and suspect opponents are weak, we add three points to our count. Then we proceed as though in the direct defensive position (partner's position), but with those three extra points.
When all your side's calls have so far been to pass, and you act in the protective position, partner must always deduct three point from their hand when considering how to continue. For this reason, the process is often referred to as 'borrowing a king'.
Because partner will always be deducting three points, we must always add three when we choose to act – it isn't optional. Otherwise, partner would have difficulty knowing how to react.
Note that three points is roughly equivalent to one trick. (40 points / 13 tricks.)
Here, we can bid 1NT, because we have a balanced hand with a virtual 16 points and decent cards in opener's suit.