The fourth, fifth and sixth periods are long periods and contain ……………
A. 18, 18 and 36
B. 18, 28 and 32
C. 18, 15 and 31
D. 18, 18 and 32
Answer:D
The fourth, fifth and sixth periods are long periods and contain ……………
A. 18, 18 and 36 B. 18, 28 and 32 C. 18, 15 and 31 D. 18, 18 and 32