Vamos analisar cada uma das opções para identificar qual delas é gramaticalmente correta: Opção A: "Was she rich, she would move to a big apartment." - Esta frase está incorreta. A forma correta seria "If she were rich, she would move to a big apartment." Opção B: "Had known he earlier it was a secret, he wouldn’t have told her that." - Esta frase também está incorreta. A forma correta seria "Had he known earlier that it was a secret, he wouldn’t have told her that." Opção C: "A: I don’t like romantic movies. B: Neither I do." - Esta frase está incorreta. A forma correta seria "B: Neither do I." Opção D: "Should she phone me, I will invite her to my party." - Esta frase está correta. É uma construção condicional que pode ser usada em inglês. Opção E: "A: I would understand him perfectly. B: So I would." - Esta frase está incorreta. A forma correta seria "B: So would I." Portanto, a opção gramaticalmente correta é: Opção D: Should she phone me, I will invite her to my party.