Transition elements form binary compoundswith halogens. Which of the following elements will form MF3 type compounds?

(a) Cr

(b) Co

(c) Cu

(d) Ni

Choose the correct option
1. (a, b)
2. (b, c)
3. (c, d)
4. (a, d)

Transition elements such as Cr and Co form binary compounds with halogens, i.e., CrF3 and CoF3 whereas Cu and Ni do not form CuF3 and NiF3.