For an endothermic reaction to be spontaneous

• An endothermic reaction can only be spontaneous under standard conditions if the increase in molar entropy is sufficient to overcome the endothermicity. 
• If $\Delta \mathrm{G}$ is negative the reaction is spontaneous. Usually this equation is dominated by enthalpy changes but in rare cases entropy can determine spontaneity.

Hence the correct answer is (B) $\Delta \mathrm{G}$ must be negative.