The demonstrators had a flower in their hands.

[azz]

a. The demonstrators had a flower in their hands.
b. The demonstrators had a flower in their hand.
c. The demonstrators had flowers in their hand.

Are these sentences grammatically correct?

In (a) each of then might be holding a single flower with both hands. But could the sentence be used if each is holding one flower with one hand?

I think (b) makes it clear that each is holding one flower in one hand. But is 'their hand' correct?

I guess (c) makes it clear that they were holding the flower or the flowers in one hand, but could it be used if they each had one flower?

 

[Barque]

Sentences a and b are unnatural.

Sentence c is ungrammatical but would work if you used "hands".

What do you want to say? Do you want to say they were each holding a single flower, or that they were all holding flowers?

 

[azz]

Thank you very much Barque.

I just wanted to figure out what the sentences meant. I use one that isn't there, but you seem to recommend.
The demonstrators had flowers in their hands.

 

[Barque]

The demonstrators had flowers in their hands.

This works. Each demonstrator may have been holding a single flower or multiple flowers.

 

[Tarheel]

You could say each held a single flower to indicate that.