In a follow-up experiment, a charge of +40 pC was placed

In a follow-up experiment, a charge of +40 pC was placed at the center of an artificial flower at the end of a 30-cmlong stem. Bees were observed to approach no closer than 15 cm from the center of this flower before they flew away. This observation suggests that the smallest external electric field to which bees may be sensitive is closest to which of these values? (a) 2.4 N>C; (b) 16 N>C; (c) 2.7 * 10-10 N>C; (d) 4.8 * 10-10 N>C.