Which of the following stanzas would enable a TCP input on port 1025, allowing traffic...

In Splunk, to configure a TCP input on a specific port and restrict traffic from certain IP addresses, you can use the acceptFrom setting. The correct stanza that enables a TCP input on port 1025 and allows traffic from all IP addresses except 10.5.5.1 would look like this:

[tcp://1025]

acceptFrom = !10.5.5.1

Here, !10.5.5.1 denotes that traffic from this IP should be denied, while all other IP addresses are allowed. Therefore, Option B is correct.

Splunk Documentation Reference: Inputs.conf - acceptFrom