During the 1970s my ex-wife Christina and I, together with our two young sons, went on a four-month guided tour through Europe, finishing in Germany to visit her parents. All passengers on the tour were_____16____ to wear a nametag, which was attache

During the 1970s my ex-wife Christina and I, together with our two young sons, went on a four-month guided tour through Europe, finishing in Germany to visit her parents. All passengers on the tour were_____16____ to wear a nametag, which was attached to a brass S-shaped logo of the travel company.
Our five-year-old son, Martin, called it his “dollar" and was_____ 17____ to keep it after the tour. When it wasn't attached to his_____ 18____ , it was pinned to the teddy bear_____ 19____ was his constant companion. One afternoon, Martin and his older brother Thomas went fora_____ 20____ through the forest with their grandfather who they_____ 21____ called Opa. Only after they'd returned home did we_____ 22____ Martin had lost his pin. The following day we set out_____ 23____ the pin but couldn't find it A very sad Martin told me a few weeks later how much he_____ 24____ his "dollar."
Some 12 years later,_ ____25_____ before starting university, Martin returned to Germany to visit his now widowed Opa, _____ 26____ constant companion was a three-year-old dog named Bello. After seeing Bello sniff one of Martin's old toys, Opa jokingly suggested they search for the_____ 27____ dollar. The previous year, a forest fire has swept_____ 28____ the area, but the pathways, brooks and old willows remained_____29 ____. Not long after heading out, Bello ran off before suddenly stopping and scratching_____30______ in the loose sand. To their delight, he'd found the brass dollar!

请回答第（25）空

A.hardly

B.only

C.even

D.just

正确答案是D