You're right, it's tricky and requires piecing together information from multiple places in the NEC (National Electrical Code). Here's how you can deduce that TFFN is indeed suitable for both dry and wet locations, and why (d) might be the correct answer if that's what the question is getting at

The Deduction Process

1. Start with Table 402.3 (Fixture Wires)

As you noted, Table 402.3 doesn't explicitly state "suitable for dry and wet locations" for TFFN. However, it does list the allowable insulation temperature rating (usually 90°C) and other properties.2.

Table 310.104(A) (Conductor Applications and Insulations)

This is the key table. Here's where the applications of different insulation types are specified: Look for "TFFN" in Table 310.104(A). You'll find it. Carefully read the description associated with TFFN in Table 310.104(A). It likely states something similar to: "Thermoplastic Fixture Wire, Nylon coated. 90°C dry, 60°C wet, 75°C oil-resistant." This means TFFN is listed as being able to be used in both dry and wet locations (with potentially a lower temperature rating in wet locations).

Why the confusion? Different Tables, Different Focus

Table 402.3 focuses on the general characteristics of fixture wires. Table 310.104(A) specifies the application and environment of conductors.

Implicit vs. Explicit Information

The NEC often relies on implicit knowledge. Just because something isn't stated directly in one table doesn't mean it's not true. You need to look for the relevant information elsewhere.

In Summary

While Table 402.3 is a starting point, Table 310.104(A) is the table that outlines where TFFN can be used. Flag for review