The core idea
Bond yields, especially real yields, affect the opportunity cost of holding gold because gold does not pay a contractual coupon.
What is happening underneath
When real yields rise, interest-bearing safe assets can become relatively more attractive; when real yields fall, that opportunity cost declines.
How investors should read it
The relationship can be disrupted by inflation fears, currency moves, geopolitical risk and safe-haven demand.
The same market move can carry different information depending on which maturity, issuer and risk premium is changing. Read the question together with the underlying concepts rather than treating one price move as a universal signal.