Which reaction has a positive dg°, assuming that entropy changes are negligible compared to enthalpy changes?

The correct answer is A.

Entropy is termed as an extensive property of the thermodynamic system. It is being related to the number of microscopic configuration which is consistent with macroscopic quantities which characterize the system.

The law of thermodynamics which states that the entropy of an isolated system which will never decrease.

(The figures missing in your question)
The Correct answer is reaction figure A (please check the attachment to see a sample figure of ΔG + wich similar to the figure that you are missing in your question )

A is the correct one as the reaction goes from the reactants at low energy state to the products at higher state of energy, so energy is added here so ΔG>0 and the reaction is endergonic. and the reaction is not spontaneous.  

It is 4.92 e-4 sorry if i am wrong

Naoh + hbr -> nabr (salt) + h2o ca (oh)2 + 2hbr - - - > ca (br)2 + 2h2o