Concept:In base B, the numeral nn means nB+n, while 100 means B2.Explanation:Let the unknown base be B.The addition becomes:1+(nB+n)=B2Rearranging gives:B2−nB−(n+1)=0Factorising:(B+1)(B−(n+1))=0Thus B=−1 or B=n+1.Since a base cannot be negative, B=n+1.Answer:The base is n+1, which is option B.