Какое предлог подходит в каждом случае в первом задании?

a. in September, b. in morning, c. at 3:30, d. in 2009, e. on April 15th, f. in Monday, g. in 1986, h. at 9:15, i. in December, j. in afternoon, k. in Easter, l. on February 21st, m. at 7:00, n. in 2003, o. in winter, p. in January, q. on Thursday, r. at night, s. on Christmas.