word choice - ~を話す to mean talk about? Confusion

メアリーと翔子は友達のトムのことを話しています。(A)

The English translation was given as "Mary and Shoko are talking about their friend Tom."

The following two sentences I guess would mean the same.

メアリーと翔子は友達のトムのことについて話しています。(B)

メアリーと翔子は友達のトムについて話しています。(C)

So how does the feeling differ between (A) and (B)? Do people say (B)? Do people say (C)?　How does the feeling differ between (B) and (C)? Would anything change if they were talking about say a test rather than their friend Tom?

Sorry, if this is a duplicate. Please help explain what's happening here! よろしくおねがいします

Answer

トムのこと has to be used when there is actually a concrete issue concerning Tom, and they're talking about that issue rather than Tom himself (i.e., if you want to say "Let's talk about the problem about Tom" rather than "Let's talk about something about Tom", you need to say トムのことを話しましょう or トムのことについて話しましょう). Otherwise, the difference between (A), (B) and (C) is very small, and they are all natural. You seem to know this, but トムを話す is incorrect.

See also: What is the こと in sentences such as あなたのことが好きだ?