To find the value of B, we need to add up the terms in the given sequence.

The pattern in the sequence is that each term alternates between adding and subtracting 3.

We can rewrite the sequence as follows:

B = (1 - 4) + (7 - 10) + (13 - 16) + ... + (103 - 100)

Now, let's group the terms together:

B = (1 + 7 + 13 + ... + 103) - (4 + 10 + 16 + ... + 100)

To find the sum of an arithmetic series, we can use the formula:

Sn = (n/2)(a + l)

where Sn is the sum of the series, n is the number of terms, a is the first term, and l is the last term.

The first term, a, is 1 and the last term, l, is 103. The common difference, d, is 6 (7 - 1 = 6).

Using the formula, we can find the sum of the first series:

S1 = (n/2)(a + l)
S1 = (n/2)(1 + 103)
S1 = (n/2)(104)

Similarly, we can find the sum of the second series:

S2 = (n/2)(a + l)
S2 = (n/2)(4 + 100)
S2 = (n/2)(104)

Since both series have the same sum, we can subtract them:

B = S1 - S2
B = (n/2)(104) - (n/2)(104)
B = 0

Therefore, the value of B is 0.