Consider the following statements:

(A) The highest oxidation state of Group 8 elements is more readily shown in their oxides than in fluorides.

(B) Fe can exist in −2 formal oxidation state also.

(C) Mn, Tc and Re easily form M(II) compounds.

The correct statement(s) is/are

Concept:-

As fluorine and oxygen are the most electronegative elements so, the highest oxidation state of any metal is found either in its chloride or oxide.

Group 8 elements include all the members of the xenon family that form oxide at a faster rate than fluoride.

Iron shows a negative oxidation state in Metal carbonyl complexes.

Example:

(i) Hieber base reaction:

\(Fe(CO)_5\:+\:NaOH\rightarrow Na[HFe(CO)_4]\:+\:CO_2 \)  

(ii) Metal Reduction:

\(Fe(CO)_5\:+\:2Na\xrightarrow[NH_3]{liq.}Na_2[Fe(CO)_4]\:+\:CO \)

Explanation:-

Fe can exist in a −2 formal oxidation state in metal carbonyl compounds

Mn, Tc, and Re easily form M(II) compounds. In transition metal series when we move from 3d to 6d, the higher oxidation state is more preferable to the lower one. Mn can produce a +2 to a +7 oxidation state but Tc and Re don't prefer a +2 oxidation state. 

Conclusion:-

Therefore A and B is the correct one.