(a) 385
As there are 4 candidates to be elected and the voter votes for at least one candidate, the voter can vote for 1 or 2 or 3 or 4 candidates out of 10 candidates.
∴ Total number of ways in which the voter can vote
= 10C1 + 10C2 + 10C3 + 4C4
= \(10+\frac{10\times9}{2\times1}+\frac{10\times9\times8}{3\times2\times1}+\frac{10\times9\times8\times7}{4\times3\times2\times1}\)
= 10 + 45 + 120 + 210 = 385.