The sentences that best show that General Buell was needed are:
- 2. The Union forces were in danger of being trapped against the Tennessee River, which was about to overflow.
- 4. They had been so successful the day before that they had expected to win easily.
The Battle of Shiloh
- The Confederates were on the verge of victory as they were trapping the Union force against the Tennessee river.
- The arrival of General Buell brought reinforcements to turn the tide.
Had General Buell not arrive in time, the Union army would have been trapped by the Confederates who expected victory as they had been successful the previous day.
In conclusion, option D is correct.
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