Correct Option: D

Given , 2 + 4 + 6 + 8 + ...... + 198 = 2 (1 + 2 + 3 + ....... + 99 )
∴ Number of terms = 99

Middle term =	99 + 1	= 50th term
	2

Middle term = 100
Second method to find the required answer with the help of formula :
It is an arithmetic series.
a = 2, a_n = 198, d = common difference = 2
Number of terms = n
∴ a_n = a + (n – 1)d
⇒ 198 = 2 + (n – 1)2
⇒ (n – 1)2 = 198 – 2 = 196

⇒ n – 1 =	196	= 98
	2

⇒ n = 99

Middle term =	99 + 1	= 50th term
	2

∴ a₅₀ = 2 + (50 – 1)2
a₅₀ = 2 + 98 = 100