I had to choose, and knew little technically about either. But Stepstone wanted royalties for developing a clone of ObjectiveC. I contacted AT&T's lawyer (William Ryan) who said I didn't need a license to develop a clone of C++. I asked if I could call it "C++" and he said sure. He laughed, and thanked me, saying I was the only one who ever bothered to ask.
So C++ it was, and Zortech C++ came out in 1988 (the first native C++ compiler for DOS, and arguably at all. g++ was out, but as a beta.)
The action for programming at the time was on DOS, and C++ pretty much exploded with the availability of an inexpensive, fast, native compiler for DOS. The comp.lang.c++ traffic grew by leaps and bounds, and comp.lang.objectivec faded away.