(12分)A、B、C、D四种物质都含有一种共同的元素，A是常见的金属，C的溶液呈现黄色，A、B、C、D之间有如下所示转化关系。

试回答下列问题：

(1)A是                    ,C是                        。

(2)C的溶液与NaOH溶液混合后的现象是                              。

(3)反应①的反应类型是        反应（选填“化合”“分解”“置换”“复分解”）。

The following data sufficiency problems consist of a question and two statements, labeled (1) and (2), in which certain data are given. You have to decide whether the data given in the statements are sufficient for answering the question. Using the data given in the statements plus your knowledge of mathematics and everyday facts (such as the number of days in July or the meaning of counterclockwise), you must indicate whether.

If  is a positive integer, what is the value of r ？（）

(1) r＜70

(2) [*]

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.