26) C

I do not think that this is on the BMAT syllabus anymore but more the knowledge, the better!

Oestrogen – thickens the lining of the uterus. 

Progesterone – maintains lining of uterus

If there is fall in progesterone, the lining of uterus would break down. 

So the order must be:

Rise in oestrogen                    High conc. of progesterone                    Fall in progesterone conc.

So the answer is C.