(?H ? K) • (H ? ?T) $\frac{\mathrm{H} \vee \sim \mathrm{H}}{\sim \mathrm{T} \vee \mathrm{K}}$

Multiple Choice

(?H ? K) • (H ? ?T) $\frac{\mathrm{H} \vee \sim \mathrm{H}}{\sim \mathrm{T} \vee \mathrm{K}}$

A) Invalid.
B) CD-valid.
C) DD-valid.
D) DA-invalid.
E) MP-valid.