Pls i will give 10 points and more who ever has a for sure answer

the table shows the results of four surveys that randomly sampled 30 teenagers about their favorite night to hang out with friends.
friday|saturday|sunday|total
survey 1|9 ═══|14|7|30
survey 2|11═══|13|6|30
survey 3|10═══|14|6|30
survey 4| 7 ═══|5|18═══|30
identify surveys that are likely biased. based on the unbiased surveys, what percent of the teenagers are likely to prefer hanging out with their friends on saturday night?
(a) 21 %
(b) 34%
(c) 38%
(d) 46