The $(r+1)^\text{th}$ term (the GENERAL term) in the expansion of $(a+b)^n$ is

1. NCERT §7.2.1 (General Term): writing out the binomial expansion term by term ($r = 0, 1, 2, \ldots$): - $T_1$: $r = 0$, term = $\binom{n}{0}\,a^n\,b^0$ - $T_2$: $r = 1$, term = $\binom{n}{1}\,a^{n-1}\,b^1$ - $T_{r+1}$: $r$-th index, term = $\binom{n}{r}\,a^{n-r}\,b^r$. 2. So the GENERAL term is $T_{r+1} = \binom{n}{r}\,a^{n-r}\,b^r$. 3. Important: the index of $T$ is $r+1$ (not $r$) — the very first term corresponds to $r=0$. 4. Option B has the powers swapped (wrong unless $b$ is the leading term). Option C has wrong binomial coefficient. Option D omits the binomial coefficient. _Source: NCERT Class 11 Mathematics, Ch 7, §7.2.1 (General Term, Eq. for $T_{r+1}$), p. 4._