We did an online survey for our seminar and for one of the questions we had a multiple choice answer possibility. I would like to find out how many people clicked at least one of the possibilities.

Is there a code that can help me with that problem?

If you have or can construct a data frame in the following form, where id represents students and A, B and C represent whether those questions were answered,

set.seed(42)
d <- data.frame(id = 1:20,
A = sample(c(TRUE,FALSE),20, replace = TRUE),
B = sample(c(TRUE,FALSE),20, replace = TRUE),
C = sample(c(TRUE,FALSE),20, replace = TRUE))

then, add a column score to indicate if at least one of A, B or C was answered (TRUE)